Kathryn Ferguson Fink (February 13, 1917 – March 28, 1989) was an American biochemist known for her work in nuclear medicine, particularly in the use of radiolabeling to study metabolism. Fink spent most of her career at the University of California, Los Angeles, often collaborating with her fellow biochemist husband Robert Morgan Fink, and was the first Ph.D. to become a Professor of Medicine at the UCLA School of Medicine. She died of cancer in 1989.