Five cases of angiomyolipoma with acute renal symptomatology have been studied using different diagnostic methods such as intravenous urogram, ultrasound, computed axial tomography. These procedures permit an adequate diagnosis of angiomyolipoma. This benign tumor may produce important symptomatology when bleeding reaches into the perinephral as well as retroperitoneal space. The identification of fat tissue within the renal tumoral lesion confirms the diagnosis of angiomyolipoma.