In the late 1960s, she was hired by Creative Management Associates (CMA), a boutique agency owned by Freddie Fields. CMA's clients included Paul Newman, Steve McQueen and Robert Redford. On December 30, 1974, Fields sold the agency to Marvin Josephson's International Famous Agency (IFA); the two companies merged to become International Creative Management (ICM). Mengers represented Candice Bergen, Peter Bogdanovich, Michael Caine, Dyan Cannon, Cher, Joan Collins, Brian De Palma, Faye Dunaway, Bob Fosse, Gene Hackman, Sidney Lumet, Ali MacGraw, Steve McQueen, Mike Nichols, Nick Nolte, Tatum O'Neal, Ryan O'Neal, Burt Reynolds, Cybill Shepherd, Barbra Streisand, Gore Vidal, and Tuesday Weld, among others. Mengers ceased to be Streisand's agent, she told the "Los Angeles Times", after a disagreement over "Yentl" (1983), which gained Oscar nominations but was not a big box-office hit. She retired from ICM in 1986 and returned to the William Morris Agency for a brief period from 1988-90.