opinion: Per Curiam.
  On June 12, 1974, respondent met for about 15 minutes with Don Connelly, a field representative of the Social Security Administration (SSA), and orally inquired of him whether she was eligible for “mother’s insurance benefits” under § 202 (g) of the Social Security Act (Act), 64 Stat. 485, as amended, 42 U. S. C. § 402 (g). Connelly erroneously told her that she was not, and she left the SSA office without having filed a written application. By the Act’s terms, such benefits are available only to one who, among other qualifications, “has filed application.” 42 U. S. C. §402 (g)(1)(D). By a regulation promulgated pursuant to the Act, only written applications satisfy the “filed application” requirement. 20 CFR §404.601 (1974). The SSA’s Claims Manual, an internal Administration handbook, instructs field representatives to advise applicants of the advantages of filing written applications and to recommend to applicants who are uncertain about their eligibility that they file written applications. Connelly, however, did not recommend to respondent that she file a written application; nor did he advise her of the advantages of doing so. The question is whether Connelly’s erroneous statement and neglect of the Claims Manual estop petitioner, the Secretary of Health and Human Services, from denying retroactive benefits to respondent for a period in which she was eligible for benefits but had not filed a written application.
  Respondent eventually filed a written application after learning in May 1975 that in fact she was eligible. She then began receiving benefits. Pursuant to § 202 (j) (1) of the Act, she also received retroactive benefits for the preceding 12 months, which was the maximum retroactive benefit allowed by the Act. Respondent contended, however, that she should receive retroactive benefits for the 12 months preceding her June 1974 interview with Connelly. An Administrative Law Judge rejected this claim, concluding that Connelly’s erroneous statement and neglect of the Claims Manual did not estop petitioner from determining respondent’s eligibility for benefits only as of the date of respondent’s written application. The Social Security Appeals Council affirmed.
  Respondent then brought this lawsuit in the District Court for the District of Vermont, which held that the written-application requirement was “unreasonably restrictive” as applied to the facts of this case. A divided panel of the Court of Appeals for the Second Circuit affirmed. 619 F. 2d 942 (1980). It agreed with petitioner as an initial matter that the regulation requiring a written application is valid and that the Claims Manual has no legally binding effect. But it considered the written-application requirement a mere “procedural requirement” of lesser import than the fact that respondent in June 1974 had been “substantively eligible” for the benefits. Id., at 948. In such circumstances, the majority held, “misinformation provided by a Government official combined with a showing of misconduct (even if it does not rise to the level of a violation of a legally binding rule) should be sufficient to require estoppel.” Ibid. In summarizing its holding, the majority stated that the Government may be estopped “where (a) a procedural not a substantive requirement is involved and (b) an internal procedural manual or guide or some other source of objective standards of conduct exists and supports an inference of misconduct by a Government employee.” Id., at 949.
  Judge Friendly dissented. He argued that the majority’s conclusion is irreconcilable with decisions of this Court, e. g., Federal Crop Insurance Corp. v. Merrill, 332 U. S. 380 (1947); Montana v. Kennedy, 366 U. S. 308 (1961); INS v. Hibi, 414 U. S. 5 (1973) (per curiam), and with decisions of other Courts of Appeals, Leimbach v. Califano, 596 F. 2d 300 (CA8 1979); Cheers v. Secretary of HEW, 610 F. 2d 463 (CA7 1979).
  We agree with the dissent. This Court has never decided what type of conduct by a Government employee will estop the Government from insisting upon compliance with valid regulations governing the distribution of welfare benefits. In two cases involving denial of citizenship, the Court has declined to decide whether even "affirmative misconduct” would estop the Government from denying citizenship, for in neither case was “affirmative misconduct” involved. INS v. Hibi, supra, at 8-9; Montana v. Kennedy, supra, at 314-315. The Court has recognized, however, “the duty of all courts to observe the conditions defined by Congress for charging the public treasury.” Federal Crop Insurance Corp. v. Merrill, supra, at 385. Lower federal courts have recognized that duty also, and consistently have relied on Merrill in refusing to estop the Government where an eligible applicant has lost Social Security benefits because of possibly erroneous replies to oral inquiries. See Leimbach v. Califano, supra, at 304-305; Cheers v. Secretary of HEW, supra, at 468-469; Goldberg v. Weinberger, 546 F. 2d 477, 481 (CA2 1976), cert. denied. 431 U. S. 937 (1977); Simon v. Califano, 593 F. 2d 121, 123 (CA9 1979); Parker v. Finch, 327 F. Supp. 193, 195 (ND Ga. 1971); Flamm v. Ribicoff, 203 F. Supp. 507, 510 (SDNY 1961). This is another in that line of cases, for we are convinced that Connelly’s conduct' — which the majority conceded to be less than “affirmative misconduct,” 619 F. 2d, at 948 — does not justify the abnegation of that duty.
  Connelly erred in telling respondent that she was ineligible for the benefit she sought. It may be that Connelly erred because he was unfamiliar with a recent amendment which afforded benefits to respondent. Id., at 947. Or it may be that respondent gave Connelly too little information for him to know that he was in error. Id., at 955 (Friendly, J., dissenting). But at worst, Connelly’s conduct did not cause respondent to take action, cf. Federal Crop Insurance Corp. v. Merrill, supra, or fail to take action, cf. Montana v. Kennedy, supra, that respondent could not correct at any time.
  Similarly, there is no doubt that Connelly failed to follow the Claims Manual in neglecting to recommend that respondent file a written application and in neglecting to advise her of the advantages of a written application. But the Claims Manual is not a regulation. It has no legal force, and it does not bind the SSA. Rather, it is a 13-volume handbook for internal use by thousands of SSA employees, including the hundreds of employees who receive untold numbers of oral inquiries like respondent’s each year. If Connelly’s minor breach of such a manual suffices to estop petitioner, then the Government is put “at risk that every alleged failure by an agent to follow instructions to the last detail in one of a thousand cases will deprive it of the benefit of the written application requirement which experience has taught to be essential to the honest and effective administration of the Social Security Laws.” 619 F. 2d, at 956 (Friendly, J., dissenting). See United States v. Caceres, 440 U. S. 741, 755-756 (1979).
  Finally, the majority’s distinction between respondent’s “substantival eligibTility]” and her failure to satisfy a “procedural requirement” does not justify estopping petitioner in this case. Congress expressly provided in the Act that only one who “has filed application” for benefits may receive them, and it delegated to petitioner the task of providing by regulation the requisite manner of application. A court is no more authorized to overlook the valid regulation requiring that applications be in writing than it is to overlook any other valid requirement for the receipt of benefits.
  In sum, Connelly’s errors “faipj far short” of conduct which would raise a serious question whether petitioner is estopped from insisting upon compliance with the valid regulation. Montana v. Kennedy, supra, at 314. Accordingly, we grant the motion of respondent for leave to proceed in forma pauperis and the petition for certiorari and reverse the judgment of the Court of Appeals.
  It is so ordered.
  This regulation has been recodified and now appears at 20 CFR §§404.602-404.614 (1980).
  This section provides, in pertinent part:
  “An individual who would have been entitled to a benefit under subsec-tio[n] . . . (g) ... of this section for any month after August 1950 had he filed application therefor prior to the end of such month shall be entitled to such benefit for such month if he files application therefor prior to the end of the twelfth month immediately succeeding such month. . . .” 42 U. S. C. §402 (i)(D-
  Judicial review of final decisions by the Secretary is authorized by 42 U. S. C. §405 (g).
  Justice Marshall cites several cases in which federal courts have applied estoppel against the Government. Post, at 791. In some of the eases, the Government had entered into written agreements which supported the claim of estoppel. E. g., United States v. Lazy FC Ranch, 481 F. 2d 985, 990 (CA9 1973); Walsonavich v. United States, 335 F. 2d 96, 100-101 (CA3 1964). In others, estoppel did not threaten the public fisc as estoppel does here. E. g.. Semaan v. Mumford, 118 U. S. App. D. C. 282, 284, and n. 6, 335 F. 2d 704, 706, and n. 6 (1964). In another, a bank claiming estoppel had erred in certain applications because it had to file before the Government would provide it with necessary information. United States v. Fox Lake State Bank, 366 F. 2d 962 (CA7 1966). We need not consider the correctness of these cases. We do think that they are easily distinguishable from the type of situation presented in this case and the line of cases we rely upon above.
  The contention was made in Caceres that a violation of an internal IRS regulation concerning electronic eavesdropping should result in exclusion from trial of the evidence obtained by such eavesdropping. In rejecting this contention, we noted that such a per se rule “would take away from the Executive Department the primary responsibility for fashioning the appropriate remedy for the violation of its regulations. But since the content, and indeed the existence, of the regulations would remain within the Executive's sole authority, the result might well be fewer and less protective regulations. In the long run, it is far better to have rules like those contained in the IRS Manual, and to tolerate occasional erroneous administration of the kind displayed by this record, than either to have no rules except those mandated by statute, or to have them framed in a mere precatory form.” 440 U. S., at 755-756.
choices: attorney general of the United States, or his office specified state board or department of education city, town, township, village, or borough government or governmental unit state commission, board, committee, or authority county government or county governmental unit, except school district court or judicial district state department or agency governmental employee or job applicant female governmental employee or job applicant minority governmental employee or job applicant minority female governmental employee or job applicant not listed among agencies in the first Administrative Action variable retired or former governmental employee U.S. House of Representatives interstate compact judge state legislature, house, or committee local governmental unit other than a county, city, town, township, village, or borough governmental official, or an official of an agency established under an interstate compact state or U.S. supreme court local school district or board of education U.S. Senate U.S. senator foreign nation or instrumentality state or local governmental taxpayer, or executor of the estate of state college or university United States State person accused, indicted, or suspected of crime advertising business or agency agent, fiduciary, trustee, or executor airplane manufacturer, or manufacturer of parts of airplanes airline distributor, importer, or exporter of alcoholic beverages alien, person subject to a denaturalization proceeding, or one whose citizenship is revoked American Medical Association National Railroad Passenger Corp. amusement establishment, or recreational facility arrested person, or pretrial detainee attorney, or person acting as such;includes bar applicant or law student, or law firm or bar association author, copyright holder bank, savings and loan, credit union, investment company bankrupt person or business, or business in reorganization establishment serving liquor by the glass, or package liquor store water transportation, stevedore bookstore, newsstand, printer, bindery, purveyor or distributor of books or magazines brewery, distillery broker, stock exchange, investment or securities firm construction industry bus or motorized passenger transportation vehicle business, corporation buyer, purchaser cable TV car dealer person convicted of crime tangible property, other than real estate, including contraband chemical company child, children, including adopted or illegitimate religious organization, institution, or person private club or facility coal company or coal mine operator computer business or manufacturer, hardware or software consumer, consumer organization creditor, including institution appearing as such; e.g., a finance company person allegedly criminally insane or mentally incompetent to stand trial defendant debtor real estate developer disabled person or disability benefit claimant distributor person subject to selective service, including conscientious objector drug manufacturer druggist, pharmacist, pharmacy employee, or job applicant, including beneficiaries of employer-employee trust agreement, employee health and welfare fund, or multi-employer pension plan electric equipment manufacturer electric or hydroelectric power utility, power cooperative, or gas and electric company eleemosynary institution or person environmental organization employer. If employer's relations with employees are governed by the nature of the employer's business (e.g., railroad, boat), rather than labor law generally, the more specific designation is used in place of Employer. farmer, farm worker, or farm organization father female employee or job applicant female movie, play, pictorial representation, theatrical production, actor, or exhibitor or distributor of fisherman or fishing company food, meat packing, or processing company, stockyard foreign (non-American) nongovernmental entity franchiser franchisee lesbian, gay, bisexual, transexual person or organization person who guarantees another's obligations handicapped individual, or organization of devoted to health organization or person, nursing home, medical clinic or laboratory, chiropractor heir, or beneficiary, or person so claiming to be hospital, medical center husband, or ex-husband involuntarily committed mental patient Indian, including Indian tribe or nation insurance company, or surety inventor, patent assigner, trademark owner or holder investor injured person or legal entity, nonphysically and non-employment related juvenile government contractor holder of a license or permit, or applicant therefor magazine male medical or Medicaid claimant medical supply or manufacturing co. racial or ethnic minority employee or job applicant minority female employee or job applicant manufacturer management, executive officer, or director, of business entity military personnel, or dependent of, including reservist mining company or miner, excluding coal, oil, or pipeline company mother auto manufacturer newspaper, newsletter, journal of opinion, news service radio and television network, except cable tv nonprofit organization or business nonresident nuclear power plant or facility owner, landlord, or claimant to ownership, fee interest, or possession of land as well as chattels shareholders to whom a tender offer is made tender offer oil company, or natural gas producer elderly person, or organization dedicated to the elderly out of state noncriminal defendant political action committee parent or parents parking lot or service patient of a health professional telephone, telecommunications, or telegraph company physician, MD or DO, dentist, or medical society public interest organization physically injured person, including wrongful death, who is not an employee pipe line company package, luggage, container political candidate, activist, committee, party, party member, organization, or elected official indigent, needy, welfare recipient indigent defendant private person prisoner, inmate of penal institution professional organization, business, or person probationer, or parolee protester, demonstrator, picketer or pamphleteer (non-employment related), or non-indigent loiterer public utility publisher, publishing company radio station racial or ethnic minority person or organization protesting racial or ethnic segregation or discrimination racial or ethnic minority student or applicant for admission to an educational institution realtor journalist, columnist, member of the news media resident restaurant, food vendor retarded person, or mental incompetent retired or former employee railroad private school, college, or university seller or vendor shipper, including importer and exporter shopping center, mall spouse, or former spouse stockholder, shareholder, or bondholder retail business or outlet student, or applicant for admission to an educational institution taxpayer or executor of taxpayer's estate, federal only tenant or lessee theater, studio forest products, lumber, or logging company person traveling or wishing to travel abroad, or overseas travel agent trucking company, or motor carrier television station union member unemployed person or unemployment compensation applicant or claimant union, labor organization, or official of veteran voter, prospective voter, elector, or a nonelective official seeking reapportionment or redistricting of legislative districts (POL) wholesale trade wife, or ex-wife witness, or person under subpoena network slave slave-owner bank of the united states timber company u.s. job applicants or employees Army and Air Force Exchange Service Atomic Energy Commission Secretary or administrative unit or personnel of the U.S. Air Force Department or Secretary of Agriculture Alien Property Custodian Secretary or administrative unit or personnel of the U.S. Army Board of Immigration Appeals Bureau of Indian Affairs Bonneville Power Administration Benefits Review Board Civil Aeronautics Board Bureau of the Census Central Intelligence Agency Commodity Futures Trading Commission Department or Secretary of Commerce Comptroller of Currency Consumer Product Safety Commission Civil Rights Commission Civil Service Commission, U.S. Customs Service or Commissioner of Customs Defense Base Closure and REalignment Commission Drug Enforcement Agency Department or Secretary of Defense (and Department or Secretary of War) Department or Secretary of Energy Department or Secretary of the Interior Department of Justice or Attorney General Department or Secretary of State Department or Secretary of Transportation Department or Secretary of Education U.S. Employees' Compensation Commission, or Commissioner Equal Employment Opportunity Commission Environmental Protection Agency or Administrator Federal Aviation Agency or Administration Federal Bureau of Investigation or Director Federal Bureau of Prisons Farm Credit Administration Federal Communications Commission (including a predecessor, Federal Radio Commission) Federal Credit Union Administration Food and Drug Administration Federal Deposit Insurance Corporation Federal Energy Administration Federal Election Commission Federal Energy Regulatory Commission Federal Housing Administration Federal Home Loan Bank Board Federal Labor Relations Authority Federal Maritime Board Federal Maritime Commission Farmers Home Administration Federal Parole Board Federal Power Commission Federal Railroad Administration Federal Reserve Board of Governors Federal Reserve System Federal Savings and Loan Insurance Corporation Federal Trade Commission Federal Works Administration, or Administrator General Accounting Office Comptroller General General Services Administration Department or Secretary of Health, Education and Welfare Department or Secretary of Health and Human Services Department or Secretary of Housing and Urban Development Interstate Commerce Commission Indian Claims Commission Immigration and Naturalization Service, or Director of, or District Director of, or Immigration and Naturalization Enforcement Internal Revenue Service, Collector, Commissioner, or District Director of Information Security Oversight Office Department or Secretary of Labor Loyalty Review Board Legal Services Corporation Merit Systems Protection Board Multistate Tax Commission National Aeronautics and Space Administration Secretary or administrative unit of the U.S. Navy National Credit Union Administration National Endowment for the Arts National Enforcement Commission National Highway Traffic Safety Administration National Labor Relations Board, or regional office or officer National Mediation Board National Railroad Adjustment Board Nuclear Regulatory Commission National Security Agency Office of Economic Opportunity Office of Management and Budget Office of Price Administration, or Price Administrator Office of Personnel Management Occupational Safety and Health Administration Occupational Safety and Health Review Commission Office of Workers' Compensation Programs Patent Office, or Commissioner of, or Board of Appeals of Pay Board (established under the Economic Stabilization Act of 1970) Pension Benefit Guaranty Corporation U.S. Public Health Service Postal Rate Commission Provider Reimbursement Review Board Renegotiation Board Railroad Adjustment Board Railroad Retirement Board Subversive Activities Control Board Small Business Administration Securities and Exchange Commission Social Security Administration or Commissioner Selective Service System Department or Secretary of the Treasury Tennessee Valley Authority United States Forest Service United States Parole Commission Postal Service and Post Office, or Postmaster General, or Postmaster United States Sentencing Commission Veterans' Administration War Production Board Wage Stabilization Board General Land Office of Commissioners Transportation Security Administration Surface Transportation Board U.S. Shipping Board Emergency Fleet Corp. Reconstruction Finance Corp. Department or Secretary of Homeland Security Unidentifiable International Entity