Miriam Wormley Lewis, 91, a retired D.C. public school teacher who was active in service organizations, died of congestive heart failure Saturday at Providence Hospital.

Mrs. Lewis began her career in the D.C. school system as an elementary school teacher. After three years, she became a clerk in the Treasury Department and then in the old War Department.

In 1920, she returned to the school system as a clerk at Dunbar High School. In 1927, she joined the faculty of Shaw Junior High, where she taught clerical practice until retiring in June 1950.

After retiring, she did volunteer work for a number of organizations, including the American Cancer Society and the Women's International Religious Fellowship, of which she was a past president.

Mr. Lewis was a native of Washington and since 1925 had lived in Ardwick, in Prince George's County. She was a graduate of Armstrong High School, Miner Teachers College and Howard University. She also earned a master's degree at New York University.

Her marriage to Clarence Lewis ended in divorce. Survivors include a son, Burton W. Lewis of Riviera Beach, Fla., two grandchildren and five great-grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Women's International Religious Fellowship, 1602 Webster St. NW, Washington, D.C., 20011.