We report a case of signet-ring cell carcinoma of the urinary bladder. A 60-year-old man was hospitalized because of total macrohematuria. Cystoscopic examination revealed a non-papillary sessile tumor on the posterior wall of the urinary bladder. The pathological diagnosis was stage pT1 signet ring cell carcinoma. Upper gastrointestinal endoscopy and computed tomographic scanning revealed no involvement of other organs. Radical cystectomy and creation of an ileal neobladder were performed. The histopathological stage was pT3aN0M0. Adjuvant chemotherapy (TS-1) was performed and the patient is currently free from disease at eight months after the surgery. This disease is usually diagnosed at an advanced stage and has a poor prognosis. To our knowledge, this is the first case report on the creation of an ileal neobladder for the treatment of primary signet-ring cell carcinoma of the urinary bladder.