Two cases of renal leiomyosarcoma were reported: The first case showed a well-encapsulated tumor with low mitotic rate. There was no tumor recurrence or distant metastasis after 30 months of follow-up. The second case had a history of left flank pain with hematuria for 10 years, and a left renal mass noted by intravenous urography (IVU) for 8 years. The specimen revealed a well-defined tumor without lymph node invasion or distant metastasis. The patient has been kept tumor free for more than 13 months. The literature concerning leiomyosarcoma of the kidney is reviewed.