Abdominal ultrasonic examination (US) was performed in 1556 patients on hemodialysis for 7 years and 6 months from April 1955 to September 1992. Renal cell carcinoma (RCC) proved histologically by operation was found in 36 patients (41 kidneys). Among the 36, RCC developed from the contracted kidney in 15, the individual kidney after renal transplantation in 3, and from ACDK (acquired cystic disease of the kidney) in 18. Among the 18 (ACDK), multiple tumors were found in the unilateral kidney in 8 and in bilateral kidney in 5. RCC was detected at the rate of 2.3% in patients on hemodialysis (1 out of 43). It was 29 time as high as in healthy persons (RCC was found in 22 out of 27933 at our Health Check-up Center, 0.079%). RCC was diagnosed 100% by US, 68% by CT, and 55% by angiography. US is the most excellent examination for the diagnosis of RCC in patients on hemodialysis.