Mamie Guyer Hammer, 90, a former public school teacher and a retired employe of the Department of the Treasury, died Friday at the National Orthopaedic and Rehabilitation Hospital in Arlington after a stroke.

A native of High Point, N.C., Mrs. Hammer taught in public schools in North Carolina for a number of years and was owner and operator of a cafeteria in High Point before moving to the Washington area in 1940. She graduated from the Whitsett Institute in North Carolina.

After moving to this area, she worked in the disbursements division of the Department of Justice here and in Philadelphia for several years and then transferred to the Treasury Department, from which she retired in 1960.

Mrs. Hammer lived in Arlington and was active in the Silver Age Club there. She was a life member of the North Carolina Congress of Parents and Teachers.

Her husband, Fowie G. Hammer, died in 1938.

Survivors include three daughters, Maxine Moore of Washington, Iris Finton of Silver Spring, and Betsy Finnegan of potomac; a son, Forrest G., of Millen, Ga., a sister, Mrs. Glenn B. Lambert of High Point, 10 grandchilden and seven great-grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Mamie Guyer Hammer Memorial Fund, Gibsonville United Methodist Church, P.O. Box 3418, Gibsonville, N.C., 27249.