Accurate staging of bladder cancer is the important factor affecting its management and prognosis. Clinicalstaging of bladder cancer consists of cystoscopic biopsy and bimanual examination during anesthesia, but this iscrude and has high rate of error. More recently, CT and US(ultrasonography) have been new means for thenoninvasive staging of bladder cancer. CT is shown to be fairly accurate in demonstrating extramural tumorextension, but it tends to overstage and cannot differentiated between mucosal and muscular involvement because ofits limited tissue specificity. However, US may be able to differentiate between mucosal and muscular involvementbecause of its high tissue specificity, and can easily provide information about involvement of prostate orseminal vesicles. Authors evaluated the efficacy of US and CT in stagingof 38 pathologically confirmed bladdercancers from June. 1984 to June, 1987. The results were as follows: 1. Overall accuracy of CT staging in bladdercancer was 77%(20/26). 2. In 15 cases of CT stage B or less cancer, 14(93%) were correct, but it was impossible todifferentiated between stage O & A, B1 or B2. 3. In 7 cases of CT stage C cancers, 3(43%) were correct, and in 4 cases of CT stage D cancers, 3(75%) were correct. 4. Overall accuracy of US staging in bladder cancer was 69%(9/13). 5. In 8 cases of US stage B2 or less cancers, 5(63%) were correct, and it was possible to differentiatebetween stage O & A, B1 or B2. 6. In 3 cases of US stage C cancers, 2(67%) were correct, and in 2 cases of USstage D cancers, 2(100%) were correct. As a result, authors considered US as a valuable addition to CT in stagingof bladder cancer.