The value of routine abdominal ultrasonography in the detection and the staging of renal cell carcinoma is described. The sonomorphologic criteria of small and large renal cell carcinomas and the potential and the limitations of pulse and colour Doppler in the evaluation of malignancy are presented. An overview of the most important conditions that need to be considered in the differential diagnosis is given. The possibilities of ultrasonic staging and follow-up after nephrectomy are mentioned. The results of multiple different studies dealing with the increased frequency of serendipitous detection of renal cell carcinoma are listed, and the consequent importance of renal ultrasonography for screening is discussed.