opinion: Justice White
  delivered the opinion of the Court.
  The Freedom of Information Act (FOIA), 5 U. S. C. § 552, mandates that the Government make its records available to the public. Section 552(b)(5) exempts from disclosure “inter-agency or intra-agency memorandums or letters which would not be available by law to a party ... in litigation with the agency.” It is well established that this exemption was intended to encompass the attorney work-product rule. The question presented in this case is the extent, if any, to which the work-product component of Exemption 5 applies when the litigation for which the requested documents were generated has been terminated.
  In 1972, the Federal Trade Commission undertook an investigation of Americana Corp., a subsidiary of respondent Grolier Inc. The investigation was conducted in connection with a civil penalty action filed by the Department of Justice. In 1976, the suit against Americana was dismissed with prejudice when the Government declined to comply with a District Court discovery order. In 1978, respondent filed a request with the Commission for disclosure of documents concerning the investigation of Americana. The Commission initially denied the entire request, stating that it did not have any information responsive to some of the items and that the remaining portion of the request was not specific enough to permit the Commission to locate the information without searching millions of documents contained in investigatory files. The Commission refused to release the few items that were responsive to the request on the basis that they were exempt from mandatory disclosure under § 552(b)(5).
  Pursuant to the Commission’s Rules, respondent appealed to the agency’s General Counsel. Following review of respondent’s request, and after a considerable process of give and take, the dispute finally centered on seven documents. Following in camera inspection, the District Court determined that all the requested documents were exempt from disclosure under § 552(b)(5), either as attorney work product, as confidential attorney-client communications, or as internal predecisional agency material. On appeal, the Court of Appeals held that four documents generated during the Americana litigation could not be withheld on the basis of the work-product rule unless the Commission could show that “litigation related to the terminated action exists or potentially exists.” 217 U. S. App. D. C. 47, 50, 671 F. 2d 553, 556 (1982).
  The Court of Appeals reasoned that the work-product rule encompassed by § 552(b)(5) was coextensive with the work-product privilege under the Federal Rules of Civil Procedure. A requirement that documents must be disclosed in the absence of the existence or potential existence of related litigation, in the Court of Appeals’ view, best comported with the fact that the work-product privilege is a qualified one. We granted the Commission’s petition for certiorari, 459 U. S. 986 (1982). Because we find that the Court of Appeals erred in its construction of Exemption 5, we reverse.
  Section 552(b) lists nine exemptions from the mandatory disclosure requirements that “represen[t] the congressional determination of the types of information that the Executive Branch must have the option to keep confidential, if it so chooses.” EPA v. Mink, 410 U. S. 73, 80 (1973). The primary purpose of one of these, Exemption 5, was to enable the Government to benefit from “frank discussion of legal or policy matters.” S. Rep. No. 813, 89th Cong., 1st Sess., 9 (1965). See H. R. Rep. No. 1497, 89th Cong., 2d Sess., 10 (1966). In keeping with the Act’s policy of “the fullest responsible disclosure,” S. Rep. No. 813, at 3, Congress intended Exemption 5 to be “as narro[w] as [is] consistent with efficient Government operation.” Id., at 9. See H. R. Rep. No. 1497, at 10.
  Both the District Court and the Court of Appeals found that the documents at issue were properly classified as “work product” materials, and there is no serious argument about the correctness of this classification. “It is equally clear that Congress had the attorney’s work-product privilege specifically in mind when it adopted Exemption 5,” the privilege being that enjoyed in the context of discovery in civil litigation. NLRB v. Sears, Roebuck & Co., 421 U. S. 132, 154-155 (1975); H. R. Rep. No. 1497, at 10; S. Rep. No. 813, at 2.
  In Hickman v. Taylor, 329 U. S. 495, 510 (1947), the Court recognized a qualified immunity from discovery for the “work product of the lawyer”; such material could only be discovered upon a substantial showing of “necessity or justification.” An exemption from discovery was necessary because, as the Hickman Court stated:
  “Were such materials open to opposing counsel on mere demand, much of what is now put down in writing would remain unwritten. An attorney’s thoughts, heretofore inviolate, would not be his own. Inefficiency, unfairness'and sharp practices would inevitably develop in the giving of legal advice and in the preparation of cases for trial. The effect on the legal profession would be demoralizing. And the interests of the clients and the cause of justice would be poorly served.” Id., at 511.
  The attorney’s work-product immunity is a basic rule in the litigation context, but like many other rules, it is not self-defining and has been the subject of extensive litigation.
  Prior to 1970, few District Courts had addressed the question whether the work-product immunity extended beyond the litigation for which the documents at issue were prepared. Those courts considering the issue reached varying results. By 1970, only one Court of Appeals had addressed the issue. In Republic Gear Co. v. Borg-Warner Corp., 381 F. 2d 551, 557 (CA2 1967), the Court of Appeals held that documents prepared in connection with litigation that was on appeal were not subject to discovery in a related case. The court also noted that there was potential for further related litigation. Thus, at the time FOIA was enacted in 1966, other than the general understanding that work-product materials were subject to discovery only upon a showing of need, no consensus one way or the other had developed with respect to the temporal scope of the work-product privilege.
  In 1970, the Federal Rules of Civil Procedure were amended to clarify the extent to which trial preparation materials are discoverable in federal courts. Rule 26(b)(3) provides, in pertinent part:
  “[A] party may obtain discovery of documents and tangible things . . . prepared in anticipation of litigation or for trial by or for another party or by or for that other party’s representative . . . only upon a showing that the party seeking discovery has substantial need of the materials in the preparation of his case and that he is unable without undue hardship to obtain the substantial equivalent of the materials by other means. In ordering discovery of such materials when the required showing has been made, the court shall protect against disclosure of the mental impressions, conclusions, opinions, or legal theories of an attorney or other representative of a party concerning the litigation.”
  Rule 26(b)(3) does not in so many words address the temporal scope of the work-product immunity, and a review of the Advisory Committee’s comments reveals no express concern for that issue. Notes of Advisory Committee on 1970 Amendments, 28 U. S. C. App., pp. 441-442. But the literal language of the Rule protects materials prepared for any litigation or trial as long as they were prepared by or for a party to the subsequent litigation. See 8 C. Wright & A. Miller, Federal Practice and Procedure § 2024, p. 201 (1970). Whatever problems such a construction of Rule 26(b)(3) may engender in the civil discovery area, see id., at 201-202, it provides a satisfactory resolution to the question whether work-product documents are exempt under the FOIA. By its own terms, Exemption 5 requires reference to whether discovery would normally be required during litigation with the agency. Under a literal reading of Rule 26(b)(8), the work product of agency attorneys would not be subject to discovery in subsequent litigation unless there was a showing of need and would thus fall within the scope of Exemption 5.
  We need not rely exclusively on any particular construction of Rule 26(b)(3), however, because we find independently that the Court of Appeals erred in construing Exemption 5 to protect work-product materials only if related litigation exists or potentially exists. The test under Exemption 5 is whether the documents would be “routinely” or “normally” disclosed upon a showing of relevance. NLRB v. Sears, Roebuck & Co. 421 U. S., at 148-149. At the time this case came to the Court of Appeals, all of the Courts of Appeals that had decided the issue under Rule 26(b)(3) had determined that work-product materials retained their immunity from discovery after termination of the litigation for which the documents were prepared, without regard to whether other related litigation is pending or is contemplated. In addition, an overwhelming majority of the Federal District Courts reporting decisions on the issue under Rule 26(b)(3) were in accord with that view. “Exemption 5 incorporates the privileges which the Government enjoys under the relevant statutory and case law in the pretrial discovery context.” Renegotiation Board v. Grumman Aircraft Engineering Corp., 421 U. S. 168, 184 (1975) (emphasis added). Under this state of the work-product rule it cannot fairly be said that work-product materials are “routinely” available in subsequent litigation.
  The Court of Appeals’ determination that a related-litigation test best comported with the qualified nature of the work-product rule in civil discovery — a proposition with which we do not necessarily agree — is irrelevant in the FOIA context. It makes little difference whether a privilege is absolute or qualified in determining how it translates into a discrete category of documents that Congress intended to exempt from disclosure under Exemption 5. Whether its immunity from discovery is absolute or qualified, a protected document cannot be said to be subject to “routine” disclosure.
  Under the current state of the law relating to the privilege, work-product materials are immune from discovery unless the one seeking discovery can show substantial need in connection with subsequent litigation. Such materials are thus not “routinely” or “normally” available to parties in litigation and hence are exempt under Exemption 5. . This result, by establishing a discrete category of exempt information, implements the congressional intent to provide “workable” rules. See S. Rep. No. 813, at 5; H. R. Rep. No. 1497, at 2.
  Respondent urges that the meaning of the statutory language is “plain” and that, at least in this case, the requested documents must be disclosed because the same documents were ordered disclosed during discovery in previous litigation. It does not follow, however, from an ordered disclosure based on a showing of need that such documents are routinely available to litigants. The logical result of respondent’s position is that whenever work-product documents would be discoverable in any particular litigation, they must be disclosed to anyone under the FOIA. We have previously rejected that line of analysis. In NLRB v. Sears, Roebuck & Co., supra, we construed Exemption 5 to “exempt those documents, and only those documents, normally privileged in the civil discovery context.” 421 U. S., at 149. (Emphasis added.) It is not difficult to imagine litigation in which one party’s need for otherwise privileged documents would be sufficient to override the privilege but that does not remove the documents from the category of the normally privileged. See id,., at 149, n. 16.
  Accordingly, we hold that under Exemption 5, attorney work product is exempt from mandatory disclosure without regard to the status of the litigation for which it was prepared. Only by construing the Exemption to provide a categorical rule can the Act’s purpose of expediting disclosure by means of workable rules be furthered. The judgment of the Court of Appeals is reversed.
  It is so ordered.
  United States v. Americana Corp., Civ. No. 388-72 (NJ). Americana was charged with violation of a 1948 cease-and-desist order in making misrepresentations regarding its encyclopedia advertisements and door-to-door sales.
  By letter to the Commission, respondent requested the following:
  “1) All records and documents which refer or relate to a covert investigation of Americana Corporation and/or Grolier Incorporated, which was made in or about April 1978, by a Federal Trade Commission consumer protection specialist named Wendell A. Reid; and
  “2) All records and documents which refer or relate to any covert investigation, made by any employee of the Federal Trade Commission, of any of the following companies: [listing 14 companies, including respondent and Americana Corporation].
  “3) All records and documents which refer or relate to any covert investigation, made by any employee of the Federal Trade Commission, of any person, company or other entity.” App. 15-16.
  “Covert investigation” was defined by respondent to be “any investigation of which the subject entity was not notified in advance and prior to acts taken pursuant to such investigation.” Id., at 16. Respondent later abandoned its requests for any documents other than those related to the Americana investigation, defined in the first category of its request.
  The requested documents are subject to mandatory disclosure as “identifiable records” under § 552(a)(3), unless covered by a specific exemption. In this case, the Commission claims exemption only under §552 (b)(5), which provides:
  “This section does not apply to matters that are—
  “(5) inter-agency or intra-agency memorandums or letters which would not be available by law to a party other than an agency in litigation with the agency . . . .”
  The Commission released a number of documents after respondent filed this suit. Respondent abandoned its claim for many others. See n. 2, supra.
  Respondent withdrew its claim for disclosure of one of the seven documents. The Court of Appeals affirmed the District Court’s judgment that another was exempt as an attorney-client communication, 217 U. S. App. D. C., at 48, n. 3, 671 F. 2d, at 554, n. 3, and held that still another was clearly a predecisional document not subject to disclosure under Exemption 5, id., at 51, 671 F. 2d, at 557. These rulings are not at issue here.
  Respondent makes some assertions concerning the ethical conduct of the Commission in continuing its investigations after the Americana suit had been instituted and claims that the work-product rule would not apply to documents containing evidence of unethical conduct. Respondent did not raise this issue before the District Court or the Court of Appeals and we decline to address it.
  See Honeywell, Inc. v. Piper Aircraft Corp., 50 F. R. D. 117 (MD Pa. 1970); Bourget v. Government Employees Ins. Co., 48 F. R. D. 29 (Conn. 1969); Stix Products, Inc. v. United Merchants & Mfrs., Inc., 47 F. R. D. 334 (SDNY 1969); LaRocca v. State Farm Mutual Automobile Ins. Co., 47 F. R. D. 278 (WD Pa. 1969); Kirkland v. Morton Salt Co., 46 F. R. D. 28 (ND Ga. 1968); Chitty v. State Farm Mutual Automobile Ins. Co., 36 F. R. D. 37 (EDSC 1964); Insurance Co. of North America v. Union Carbide Corp., 35 F. R. D. 520 (Colo. 1964); Hanover Shoe, Inc. v. United Shoe Machinery Corp., 207 F. Supp. 407 (MD Pa. 1962); Thompson v. Hoitsma, 19 F. R. D. 112 (NJ 1956); Tobacco and Allied Stocks, Inc. v. Transamerica Corp., 16 F. R. D. 534 (Del. 1954).
  See In re Murphy, 560 F. 2d 326, 334 (CA8 1977); United States v. Leggett & Platt, Inc., 542 F. 2d 655 (CA6 1976), cert. denied, 430 U. S. 945 (1977); Duplan Corp. v. Moulinage et Retorderie de Chavanoz, 487 F. 2d 480, 483-384 (CA4 1973). See also In re Grand Jury Proceedings, 604 F. 2d 798, 803 (CA3 1979) (work-product privilege continues at least when subsequent litigation is related). Cf. Kent Corp. v. NLRB, 530 F. 2d 612 (CA5) (work-product privilege does not turn on whether litigation actually ensued), cert. denied, 429 U. S. 920 (1976).
  See In re Federal Copper of Tennessee, Inc., 19 B. R. 177 (Bkrtcy. MD Tenn. 1982); In re International Systems & Controls Corp. Securities Litigation, 91 F. R. D. 552 (SD Tex. 1981); United States v. Capitol Service, Inc., 89 F. R. D. 578 (ED Wis. 1981); In re LTV Securities Litigation, 89 F. R. D. 595 (ND Tex. 1981); First Wisconsin Mortgage Trust v. First Wisconsin Corp., 86 F. R. D. 160 (ED Wis. 1980); Panter v. Marshall Field & Co., 80 F. R. D. 718 (ND Ill. 1978); United States v. O. K. Tire & Rubber Co., 71 F. R. D. 465 (Idaho 1976); SCM Corp. v. Xerox Corp., 70 F. R. D. 508 (Conn.), appeal disxn’d, 534 F. 2d 1031 (1976); Burlington Industries v. Exxon Corp., 65 F. R. D. 26 (Md. 1974). See also Hercules, Inc. v. Exxon Corp., 434 F. Supp. 136 (Del. 1977) (protected when cases are closely related in parties or subject matter); Ohio-Sealy Mattress Mfg. Co. v. Sealy, Inc., 90 F. R. D. 45 (ND Ill. 1981) (protected in later related litigation).