We report the cytologic features of a case of primary small cell carcinoma of the urinary bladder with high grade transitional cell and signet ring cell carcinomatous components. A 64-year-old male presented with gross hematuria for one week. Computed tomography revealed an ill-defined mass in the left lateral wall of the urinary bladder. Urinary cytology showed hypercellularity with predominantly isolated single cells and clustered cells. They have scanty cytoplasm and naked hyperchromatic nuclei with finely granular nuclear chromatin and rare nucleoli. The tumor cells occurred predominantly singe cells, but a few in clusters. Nuclear molding was prominent. No glandular formation or nesting was noted. The second tumor cells had high nuclear/cytoplasmic ratio, irregular nuclear membrane, and coarse granular chromatin. The background was inflamed and necrotic. The histoiogic findings of transurethral resection were mainly composed of small cell carcinoma, and partly transitional cell and signet ring cell carcinomatous components. Small cell neuroendocrine carcinoma have distinctive cytologic features to make a proper diagnosis.