Renal angiomyolipoma (hamartoma) is an uncommon benign tumor of the kidney. Although about 400 cases of renal angiomyolipoma have been reported, it still causes difficulties in diagnosis and treatment. Until a few years ago it was almost impossible to arrive at a correct diagnosis preoperatively, and most of the cases underwent nephrectomy with the wrong diagnosis of renal carcinoma. More recently, abdominal computerized tomography and renal sonography have made it possible to reach the correct preoperative diagnosis in many cases, and thus to avoid unnecessary nephrectomies. We report on our experience with 13 cases of renal angiomyolipoma, and our conservative approach in a number of cases, which has enabled us to preserve renal tissue and function.