We reported 10 cases of renal angiomyolipoma (AML). Selective renal biopsy was performed on three cases of them. Two of the three cases were diagnosed of AML by histological evaluation in the biopsied specimen. In the remaining one case, histology by biopsy showed medullary fibroma and finally diagnosed of AML by nephrectomy. 7 cases on which no biopsy was performed could not be correctly diagnosed preoperatively and open surgery (6 nephrectomy and 1 partial nephrectomy) was performed. Although selective renal biopsy has some limitation, it provides very important information for the diagnosis of AML and results in avoiding unnecessary nephrectomy.