BackgroundThe urinary bladder's mixed neuroendocrine-non-neuroendocrine neoplasm is a sporadic malignant tumor. Because of its rare incidence rate, the optimal treatment options for patients with mixed neuroendocrine-non-neuroendocrine neoplasm of the urinary bladder remain unknown.Case presentationA 61-year-old man was diagnosed with bladder cancer by cystoscopy due to painless gross hematuria. The patient then underwent transurethral resection of the bladder tumor. The postoperative pathological and immunohistochemical examination confirmed a mixed neuroendocrine-non-neuroendocrine neoplasm of the urinary bladder with small cell carcinoma and urothelial. The patient finally received radical cystectomy and cisplatin plus etoposide chemotherapy. There was no recurrence and metastasis three months after the operation.ConclusionThis case is a rare and high-risk pathological type of bladder malignant tumor. After radical cystectomy and postoperative adjuvant treatment, there was no tumor recurrence and metastasis three months after the operation. Radical cystectomy is still the preferred treatment for high-risk bladder cancer without distant metastasis.