Leiomyosarcoma of the kidney is a rare entity with poor prognosis. Among renal sarcomas, it is the most common histologic subtype amounting to 50-60% of all cases. The tumors usually arise from either the renal capsule or smooth muscle tissue in the renal pelvic wall. We describe a case of renal leiomyosarcoma that presented with history of left flank pain. Physical examination was normal. Abdominal ultrasound showed a solid lesion of 38 x 36 mm arising from the left kidney. Intravenous urography showed cut off of both major and minor calyces of the left kidney from its pelvis with a normal right kidney. Exploratory laparotomy revealed a well-encapsulated mass confined to the renal parenchyma for which radical nephrectomy was performed. Histopathology showed a Grade I leiomyosarcoma arising from the renal capsule. Adjuvant chemotherapy and sandwich radiotherapy was given and he is disease free after six and half years of follow up. The rarity of this disease, its severity and poor prognosis, uncommon form of presentation, resulting delay in diagnosis and difficulty in management is highlighted and reported.