A 69-year-old woman visited our hospital with a chief complaint of fever. Five years ago, she was diagnosed as ascending colon cancer and received right hemi-colectomy. One year later, local recurrence with right hydronephrosis was detected, and she received chemotherapy -4 cycles of modified fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus bevacizumab, and 12 cycles of fluorouracil, leucovorin, and irinotecan (FOLFIRI) plus bevacizumab- for two years. Local recurrence and right hydronephrosis disappeared on positron emission tomography performed 4 years postoperatively. This time, abdominal computed tomography for investigation of fever showed a relapse of right hydronephrosis and pyonephrosis. Cystoscopy revealed non-papillary tumor from the right ureteral orifice. Pelvic magnetic resonance imaging showed multiple tumors in the right ureter, and the distal lesion projecting into the bladder. After the general condition became well by right nephrostomy for infection control, transurethral resection of bladder tumor was performed. Histological examination of the specimen revealed a metastatic tubular adenocarcinoma (colon origin). Although right nephrectomy was performed for pyonephrosis control, she died of local progression of ascending colon cancer 10 months after first visit. Intraluminal ureteral progression of carcinoma originating from organs other than urinary tract is very rare. To our knowledge, this is the 9th report in the English or Japanese literature. In this case we could not rule out primary ureteral cancer preoperatively, and histological examination revealed intraluminal ureteral dissemination of ascending colon cancer.