Joyce M. Raffa, 71, a medical technician with the Montgomery County Health Department for almost 30 years, died of cancer Monday at the Bethesda Naval Hospital.

Mrs. Raffa was a volunteer in several service organizations in addition to her medical work. They included Planned Parenthood, the League of Women Voters and the "Meals on Wheels" program for elderly persons who have difficulty in leaving their homes.

She also was a member of St. John's Church in Bethesda. She was chairman and secretary-treasurer of the church's Opportunity Shop and was active in the Women of St. John's organization.

Mrs. Raffa was born in Meriden, Conn. She came to the Washington area in 1930 following her marriage to Aldo L. Raffa. The couple had lived in Bethesda since 1936.

Mrs. Raffa became a medical technician with the Montgomery County Health Department in 1943. She retired in 1972.

Besides her husband, of the home in Bethesda, survivors include a son, John B., of Ventura, Calif., and a daughter, Joyce H., of Springfield, Mass.

The family suggests that expressions of sympathy be in the form of contributions to the S. John's Church Memorial Fund, Bethesda, or to a charity of one's choice.