The course of patients suffering from renal cell carcinoma depends on various factors. The measurement of the nuclear DNA content has been considered as a prognostic indicator in addition to morphologic and clinical parameters. The meaning of this parameter is under discussion today. The aim of the present study is to investigate the influence of nuclear DNA parameters of renal cell carcinoma on the prognosis. It should be searched for such parameters which give us the possibility to divide the patients into a low-risk-group and a high-risk-group. 110 clear cell renal carcinomas were investigated by means of image analysis and flow cytometry. Stemline ploidy, 5c-exceeding-rate, DNA grade of malignancy, S-phase-fraction, proliferating fraction, and nuclear area have been determined. A significant correlation between the size of the tumor, lymph node metastases and distant metastases on the one hand and the computed DNA parameters on the other hand was found. A similar correlation between histologic grading and DNA parameters could be found. There were pieces of information about the clinical follow-up in 87 patients (mean follow-up time 15,5 months). Local recurrence occurred in 12 cases. The computed differences between DNA parameters and local recurrence were not significant. Further clinical follow-up and clinical re-examination of all patients will be performed. Then we can decide, if it is possible to make a division into low-risk and high-risk cases based on DNA parameters.