Margaret Brooke, 85, a former administrator with social service agencies, died of cardiac arrest April 30 at Montgomery General Hospital. She lived in Sandy Spring, Md.

In the 1950s, Miss Brooke was admitting director of Children's Hospital in Washington. She retired there in 1956. Later she worked part time at Montgomery General Hospital, where she helped set up the department of social services.

Miss Brooke was born in Sandy Spring. She attended Sweetbriar College in Virginia. She at one time was with the Social Service League in Montgomery County.

She had worked in Austria with the American Friends' Service Committee relief program after World War I. Later she was with children's social service agencies in this area and in Pennsylvania. These included the D.C. welfare department and the state emergency relief administration in Harrisburg.

Miss Brooke took undergraduate work at the New York School of Social Work and earned a degree from the University of Maryland in 1942. She then held various positions with the American Red Cross here.

In recent year, she had served on the board of directors of the Sandy Spring Friends' School.

She is survived by a sister, Mrs. Charles C. Tumbleson of Sandy Spring.

The family suggests that expressions of sympathy be in the form of contributions to Sandy Spring Friends' School.