14C stearic acid was incubated in organ culture of rabbit lens for 6, 12 and 20 hours. Stearic acid did penetrate the lens and was incorporated into triacyl-glycerides and phospholipids. It also served as a carbon source for cholesterol synthesis. Individual fatty acids were isolated and radioactivity measurements were made. Incorporation of label was found in C12:0, C14:0 and C16:0 fatty-acids, indicatingde novosynthesis in the lens; incorporation was found in C16:1 and C18:1, indicatingδ9 desaturase activity, and incorporation was found in the fatty acids of 20 carbons or longer, indicating the presence of a fatty acid elongation system in the lens.