Effect of whole body gamma irradiation (1200 r) and the effect of administration cystamine prior to irradiation has been studied on kidney total lipids, cholesterol, phospholipids (phosphatidylcholine and phosphatidylethanolamine). Irradiation significantly decreases kidney cholesterol and this decrease was not prevented by administration of cystamine prior to irradiation. Irradiation did not affect the incorporation of NaH232PO4 into kidney phosphatidylcholine and phosphatidylethanolamine but the incorporation of glucose-U-14C was significantly reduced in kidney total lipids and phosphatidylcholine. Administration of cystamine before irradiation was ineffective in modifying the incorporation of glucose-U-14C into kidney lipids and phosphatidylcholine.