Dr. Francis Weston Blackwell Sr., 60, who had practiced internal medicine in Washington for 21 years and taught at Howard University's medical school from 1960 to 1972, died Thursday at the Greater Southeast Community Hospital after a stroke. He lived in Hillcrest Heights.

During his years on the Howard faculty, Dr. Blackwell taught courses in physiology, biomedics, and oncology. He had been a fellow of cardiovascular diseases and chief internal medicine resident at Howard University's hospital from 1958 to 1960.

He was secretary-treasurer of the internal medicine department and of the medical staff of the Greater Southeast Community Hospital.

Dr. Blackwell was a member of the Bethel Circle at the Shiloh Baptist Church in Washington.

He was a native of Columbia, S.C. and came to Washington in 1940. He served with the Army in North Africa and Italy during World War II. Dr. Blackwell was a 1950 graduate of Howard University where he earned a bachelor's degree in zoology and chemistry. He graduated from Howard's medical school in 1955.

Survivors include his wife, Mary M. of Hillcrest Heights; two daughters, Vicki B. Washington of Cincinnati; Brenda M. of Hillcrest Heights; Army SGt. Francis W. Jr. of Hagerstown; his mother, Lillie Blackwell of Washington; four brothers, Robert H. of Los Angeles, and Preston E., Samuel M., and Harold D., all of Washington, and two grandchildren.