Frances C. Blacklow, 64, a retired area teacher who served as president of the D.C. Congress of Parent-Teachers Associations from 1961 to 1963, died Friday at Georgetown University Hospital. She had suffered from cancer.

She had taught at a number of Washington public elementary and junior high schools, including Janney Elementary, for 17 years before retiring in 1972.

Mrs. Blacklow then taught three years at the Jewish Day School before retiring a second time in 1975.

She helped leawd a drive by the Philip M. Stern Family Fund to upgrade reading materials in D.C. public schools during the 1960s.

Mrs. Blacklow also had served on Washington's Public Health Advisory Council during the mid-1960s. She belonged to the D.C. Citizens for Better Public Education.

She was a native of Boston and moved here in 1939.

She is survived by her husband, Arthur M. Blacklow of the home in Washington; two sons, William B. of Chevy Chase and Roger D. of Baltimore; a daughter, Laura A. of Cambridge, Mass.; two sisters, Sarah Greenglass and Lillian Cohen, both of Boston and Sam Cohen of Newton, Mass., and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Patients' Emergency Fund at the National Institutes of Health, or the Vincent P. Lombardi Cancer Research Center at Georgetown University Hospital.