A 50-year-old man presented with asymptomatic gross hematuria which he had first noticed 3 months earlier. Clinical examinations revealed a non-papillary, broad-based tumor on the left lateral wall of the urinary bladder with a clinical stage of T3N0M0. The pathological diagnosis of a transurethral biopsy tissue specimen was small cell carcinoma. Neoadjuvant intraarterial infusion chemotherapy using cisplatin and adriamycin was initially administered but proved to be ineffective. Thus, we performed a radical cystectomy. The tumor tissue was apparently homogenous and composed of small cells arranged in sheets and solid patterns, and was staged to be pT3bR1L2V0N0. An electron microscopic study confirmed small cell carcinoma with neurosecretory granules. Postoperatively, 4 courses of adjuvant chemotherapy consisting of cisplatin, etoposide and ifosfamide were administered. The patient is alive without any evidence of tumor recurrence 26 months after the operation.