Irene Mildred Pepper, 74, wife of Rep. Claude Pepper (D-Fla.) and member of charitable, civic, and political organizations, died of cancer Saturday in the Miami Heart Institute in Miami Beach, Fla.

Mrs. Pepper was characterized as "one of the original liberated women," by First Lady Rosalynn Carter.

Speaking at a testimonial dinner in honor of Mrs. Pepper and her husband last September, Mrs. Carter said, "mildred Pepper has had a career in public service all her own, a succession of volunteer, nonremunerative jobs."

Mrs. Carter added, "her membership in organizations devoted to serving cancer research, Parkinson's disease, the Red Cross, USO, United Nations, ecology and beautification, 4-H activities and the labor movement indicate her wide range of interests and concerns."

Mrs. Pepper had been vice president and president of the Women's National Democratic Club of Washington, and belonged to both the Democratic Congressional Wives Forum and the Congressional Club of Washington.

She was the National Chairman of the Women's Division of the National Parkinson Foundation and was National Chairman of the annual Bob Hope Dinner held in Miami Beach to raise funds for the Foundation.

She had been a member of the Senate Wives Red Cross Group during World War Ii, and done volunteer work for both the National Heart and Cancer Institutes.

Mrs. Pepper attended the 1946 Paris Peace Conference as a delegate of an organization representing women of the Western Hemisphere. While attending the conference she interviewed then Soviet Foreign Minister V. M. Molotov for the old International News Service.

In Miami, she had served as vice chairman of the city's Committee on Ecology and Beautification, and served on the board of the University of Miami's Women's Cancer Association.

Mrs. Pepper was a native of Opp, Ala., and came to Florida with her parents in 1920. She attended Florida State University in Tallahassee where she later helped establish the school's Fashion Institute.

She married Rep. Pepper in 1936. He represented Florida in the U.S. Senate from 1937 to 1951, and has been a member of the House of Representatives since 1963.

Mrs. Pepper accompanied her husband on a number of trips abroad and had attended every Democratic National Conventions since 1920.

In addition to her husband, of the homes in Washington and Miami; she is survived by a brother, Clyde Webster, of Arlington, and a sister, Mrs. Ben Fuller, of Spring Hill, Fla.