The aim of this study is to evaluate the diagnostic value of percutaneous biopsies of renal masses with comparison of pathological data between the biopsies and the surgical specimens. Thus, we retrospectively studied 73 biopsies of patients, who were referred to our institution between 1995 and 1997. The mean age of the patients was 60 +/- 14 years with a male predominance (67%). Twenty per cent of the biopsies were negative. Eleven per cent of the biopsies were benign lesions (oncocytoma, angiomyolipoma, infectious lesions). For renal cell carcinomas, the correlation coefficient between biopsy histology and final pathology was 0.87. Conversely, it was only 0.36 for the Führman grading. Nevertheless, low (1-2) and high (3-4) grades were accurately separated (0.92). We conclude that the percutaneous biopsy is a useful tool for diagnosis of renal masses.