Fifteen cases of renal angiomyolipoma seen between May, 1988 and October, 1994 in our hospital are presented. Surgical treatment was performed in 6 cases, 1 of which was falsely diagnosed as liposarcoma by frozen specimen during the operation. Nine cases were only followed-up by ultrasonography and/or computed tomography. In 2 cases, in which enucleation was performed after a follow-up period of more than one year, tumors were inclined to grow rapidly. In 5 cases, which were not operated and followed-up for more than one year, tumors were inclined to grow very slowly.