The simultaneous occurrence of renal collecting duct (Bellini duct) carcinoma and bladder urothelial carcinoma is very rare. A 68-year-old female patient with bladder urothelial carcinoma first received transurethral resection of the tumor. Left side nephrouretectomy and transurethral resection of the intramural ureter were performed 8 months later under the diagnosis of concomitant renal pelvic urothelial carcinoma. However, the final pathologic examination revealed collecting duct carcinoma. The patient received systemic chemotherapy after surgery, but distant metastasis was noted 6 months later. Here, we report a rare case of combined renal collecting duct carcinoma and bladder urothelial carcinoma confirmed by pathologic examination and immunohistochemical staining.