Triacylglycerol lipase activities in adrenals and testes of rats were measured and the properties of the enzymes were characterized. The enzymes were extracted from acetone-ether dried powder of the tissues and the crude extracts were applied to a heparin-Sepharose affinity column. The enzymes bound to the column were then eluted at different ionic strengths. Two lipases could be detected in rat adrenals: one was inactivated by the antiserum raised against hepatic triacylglycerol lipase and the other had the properties of lipoprotein lipase. In testes, only lipoprotein lipase could be detected. The results are discussed in connection with the possible functions of these two lipases in organs utilizing lipoprotein-cholesterol for steroid hormone synthesis.