Twelve young rhesus monkeys weighing 1.5-2.0 kg were acclimatised for a month in the animal house of the Institute. After acclimatization 6 monkeys were placed on a protein calorie deficient diet and remaining 6 on normal diet. The deficiency state was indicated by reduction in body weight, significant decrease in serum albumin, lack of physical activity and shedding of fur. At this stage, animals of both groups were sacrificed and brains were removed. Cerebrum was separated, blotted on filter paper and weighed. In vitro incorporation of (U-C14)-glucose was done for 2 hr in approximately 300 mg cerebrum. Incorporation of this precursor was determined in cerebrum, lipids, its fractions and proteins in both groups. There was increased incorporation of (U-C14)-glucose into tissue, gangliosides, free fatty acids and esterified cholesterol but no significant change in myelin marker lipids and proteins in PCM group was noticed as compared to age matched controls.