Cytologic-nucleolar grading of carcinomas includes mitotic frequency, mean nuclear size, nuclear variability, degree of chromasia and nucleolar frequency, and the occurrence of singular or multiple, small or large nucleoli in the central or peripheral location. A total of 186 renal cell carcinomas were analyzed cytologically in this respect. The results were correlated to the histologic pattern, tumor stage, and grading. Renal cell carcinomas of low malignancy and stage possess a low nucleolar frequency and small solitary nucleoli in the central location. Highly malignant carcinomas (T3 or T4) are characterized by high nucleolar frequency and multiple prominent nucleoli in the eccentric position. There is no correlation to the histologic pattern. Therefore, the nucleolar status is helpful in grading and determination of prognosis of renal cell carcinomas.