The effect of feeding mustard oil, coconut oil and sesame oil along with cholesterol, on the different fractions of plasma lipids was studied in rhesus monkeys. These oils are commonly used in India. Fecal cholesterol and the different plasma lipids were estimated at intervals up to 6 months. Supplementation of cholesterol feeding with mustard and coconut oils raised plasma cholesterol and reduced fecal cholesterol to the same degree. The above changes were most marked when the animals were fed sesame oil. A relative decrease in the alpha-lipoprotein % to beta-lipoproteins was observed in monkeys fed the different oils. Plasma nonesterified fatty acids increased after cholesterol feeding and was highest in animals fed sesame oil. The iodine number of the different oils was: mustard oil, 104; coconut oil, 9; and sesame oil, 110. The depressant effect of the different oils on plasma cholesterol level does not seem to be due to saturation, unsaturation or fatty acid composition of the oil.