We report a case of calcium oxalate deposition in a renomedullary interstitial cell tumor (RICT) in a patient dying of full-blown AIDS. The precipitates showed birefringence using a partially polaris ed light and were stained black in Yasue's silver nitrate-rubeanic acid method. The combination of calcium oxalosis and RICT has not been reported before and might possibly be due to systemic biochemical alterations of the glycosaminoglycans as a result of profound metabolic disturbances in AIDS patients.