Frances Bell Johnson, 72, a residnet of the Washington area for 45 years and a federal employe for 20 years, died of cancer Wednesday at the Collingswood Nursing Center in Rockville.

Mrs. Johnson was born in Bedford, va. She moved to Baltimore after attending a business college in Roanoke, Va., and worked for the Maryland State Board of Education.

In 1934, she moved to Washington and went to work for the old Home Owners Loan Corp. During World War II she transferred to the War Production Board.

In 1963, she joined the old Army Map service and remained there until her retirement in 1971. She then was a guide at Decatur House on Lafayette Square and at the nearby Octagon house, which President James Madison used as his residence after the British burned the White House in the War of 1812.

Mrs. Johnson was a member of the Altar Guild of St. David's Episcopal Church in Washington. She also had been a volunteer fund-raiser for Children's Hospital and the American Cancer Society.

Survivors include her husband of 43 years, Wheeler Johnson, of the home in Brookmont, Md.; a son, Wheeler Jr., of Frederick, Md.; a daughter, Roberta Ludwig, of Derwood, Md.; two sisters, Gretchen Matthews, of Baltimore, and Lucy Bloom, of Austin, Tex., and one grandson.

The family suggests that expressions of sympathy be in the form of contributions to the Memorial Fund of St. David's Episcopal Church, or to the American Cancer Society.