Small cell carcinomas are not uncommon in the lungs, and they usually respond to systemic chemotherapy well. However, primary small cell carcinomas of the urinary tract are rare. We analyzed the clinical data of 7 patients who suffered from primary small cell carcinoma of the urinary b ladder in our hospital since 1998. All of them presented with gross hematuria as the initial symptom, and all of the tumors were found without difficulty via either urography or cystoscopy. Since the behavior of the tumor 15 usually aggressive, a more-advanced treatment strategy including adequate surgery and adjuvant therapy 15 highly recommended.