Dr. Feodore Lynen, 68, a German biochemist who was the cowinner of the 1964 Nobel Prize for medicine and physiology died of kidney failure Monday in Munich.

Dr. Lynen and Dr. Konrad E. Bloch of Harvard University were awarded the Nobel Prize for "contributions to understanding the mechanism and regulation of cholesterol and fatty acid metabolism."

Dr. Lynen and Dr. Bloch began research on cholesterol independently in the early 1940s, hoping to clarify the biosynthesis of the substance. Their work was considered important because it led to a greater understanding of the chemistry of life and helped open windows on the possible cause of disease of the heart and circulatory system.

The Nobel committee also cited Dr. Lynen for his "recent discovery of the biochemistry by which the vitamin biotin acts." Biotin plays a role in the production of fat and the committee said Dr. Lynen's discovery had the most far-reaching implications."

His research over the years also included studies on fermentation and the critic acid cycle. His work on the metabolism of fatty acids helped explain the chemical reactions through which energy is produced when fatty acids in foods are burned up to produce carbon dioxide and water.

Dr. Lynen was born in Munich. He earned his doctoral degree at the University of Munich, where he had taught since 1942. He also served as director of the Max Planck Institute for Cellular Chemistry from 1954 to 1972.

In 1960, he visited this country and lectured at the universities of Illinois and Wisconsin. CAPTION: Picture, DR. FEODORE LYNEN