Oxandrolone, an anabolic steroid, significantly reduced serum triglycerides in type III, IV, and V hyperlipoproteinemia, with a concomitant decrease in pre-beta lipoproteins. Its slightly enhancing effect on serum cholesterol and absolute increase in beta lipoproteins might eventually discourage its administration in type II patients. Alpha lipoproteins always remained at low levels. In addition to its hypotriglyceridemic action,, oxandrolone induced a slight reduction in uric acid and alkaline phosphatases. Untoward side effects were not observed even after prolonger therapy. Therefore, oxandrolone might deserve a place among the few available triglyceride-reducing therapies.