Margaret Warriner Wells Terrell, 70, a longtime Washington resident who was active in service organizations, died Thursday at her home in Atlanta of Alzheimer's disease, a disorder of the nervous system.

Mrs. Terrell was born in Crewe, Va., and attended the University of Virginia. She moved to Washington to study at the George Washington University School of Nursing. After graduation, she was licensed as a registered nurse. She was a nurse at George Washington University Hospital before her marriage in 1934 to Dr. William Dandridge Terrell Jr., a physician here.

Following her marriage, Mrs. Terrell devoted her time to her family. She also was a member of St. David's Episcopal Church and its Altar Guild, the Virgie Webster Circle of the Florence Crittenton Home, the George Washington University Women's Board, of which she was a secretary and treasurer, and the Medical Auxiliary of George Washington University.

In addition, she was a member of the Washington Golf and Country Club, the Washington Club and the Columbia Country Club here and the Farmington Country Club in Charlottesville, Va.

Mrs. Terrell lived in Washington until 1976, when she moved to Atlanta to be near her family.

Her husband died in 1969.

Survivors include two daughters, Nancy Terrell Elsas of Atlanta, and Dandridge Terrell Penick of Lexington, Va.; one sister, Mrs. Walter L. Eubank Sr. of Crewe, and five grandchildren.