Retrospective study on the frequency of associated bladder cancer and the influence on the prognosis was carried out in 170 cases of renal pelvic and ureteral cancer. The number of cases of associated bladder cancer coexistent with renal pelvic and ureteral cancer was 31 (18.2%), and the number of subsequent cases 3 (19.4%). The frequency of occurrence of the primary tumor site was 27.2% in the renal pelvis, 45.6% in the ureter and 58.3% in both renal pelvis and ureter. Multiple tumors occurring in the renal pelvis and ureter occupy a high percentage. As for the degree of differentiation, many cases were subsequent to G1. As for the stage, a few cases with bladder cancer were subsequent to T4, but there was no definite tendency in the occurrence of bladder cancer. The prognosis of renal pelvic and ureteral cancer: the 10-year survival rate was 93.3% for G1, 66.6% for G2 and 12.4% for G3. As can be seen, there was good correlation with the pathological gradings. It must be remembered, however, that 5-year survival rates in cases of associated bladder cancer of coexistent type, in cases of subsequent type and in cases without associated bladder cancer were 56.2%, 72.7% and 64.8%, respectively: there was no significant difference. Bladder cancer associated with renal pelvic and ureteral cancer makes the therapy troublesome, but no influence on the prognosis was observed. Therapy in conformity with the pathological grading and stage is regarded as particularly important in cases of associated bladder cancer.