Rats were raised for 2 generations on a diet in which 1.25% methyl linoleate was the only source of fat. Control rats were given 1.0% methyl linoleate plus 0.25% methyl linolenate. Lipids were extracted from retinas and their fatty acids were analyzed by gas-liquid chromatography. Docosahexaenoic acid accounted for 33.8% of total fatty acids in control retinas, for 13% of fatty acids in first-generation deficient retinas, and for 2.7% of fatty acids in second-generation deficient retinas.