We reviewed 76 cases of renal pelvic and ureteral cancer, admitted to our hospital between January, 1975 and December, 1988, with special reference to the occurrence of bladder cancer. Bladder cancer was associated with an upper urinary tract neoplasm in 35 of the 76 cases (46.1%), 7 with a preceding bladder cancer, 17 with a coexistent one and 11 with a subsequent one. In case of renal pelvic and upper ureteral cancer the incidence of coexistent or subsequent tumors of the bladder was 28.7% (16 of 56 patients). However, in the cases of lower ureteral cancer the incidence of these tumors was 82.4% (14 of 17 patients). This incidence was significantly higher than that in renal pelvic and upper ureteral cancer. The subsequent bladder cancer was observed in 19 patients including 8 patients who had a recurrence of the bladder cancer after the treatment for a preceding and coexistent bladder cancer. The cancer in most cases occurred within 2 years after the treatment of the upper urinary tract neoplasm. Of 19 patients who had subsequent bladder cancer 11 had primary sites in the renal pelvis and upper ureter. Another 8 patient had primary sites in the lower ureter. Four of the 8 subsequent bladder cancers in patients with lower ureteral cancer occurred just on and around the affected ureteral orifice. All these 4 tumors were high grade and high stage tumors. On the other hand, another 15 patients developed subsequent bladder cancer in a place other than the affected ureteral orifice. Of these 15 patients, 13 cases showed a low grade and low stage tumor.(ABSTRACT TRUNCATED AT 250 WORDS)