A prospective study evaluates screening investigations of the kidneys of 2350 patients. Sonographic criteria of the renal pelvic tumour are established. So-called "indirect signs" are only recognized by the compound scanner. By these ultrasonic symptoms a pelvic tumor could be detected with 15 patients which is a frequency of 6,5%. Part of the patients were preselected. The possibility of false-negative findings remains unconsidered. The study proves the great relevancy of ultrasonography in this disease. When operations of renal pelvic carcinomas were retrospectively checked our diagnostic results were underlined.