The frequency of malignancy grade I-III (grading system according to Böcking and Sommerkamp, 1980) and of clinical stages T0-T3 in 393 unselected prostatic carcinomas (227 punch biopsies and 166 transurethral resections) were investigated over a period of 2 years. G III carcinomas were represented most frequently in the whole material (54%) as well as in punch biopsies (62%). G I carcinomas with a favorable prognosis make up 20% of the tumors in the whole material and only 10% in punch biopsies. In contrast, 54.9% of incidental carcinomas (T0) are G I tumors, 18.6% G III carcinomas with an unfavorable prognosis. The advanced clinical stages T2 and T3 predominate in the whole material with 62.4%, compared to stages T0 and T1 comprising 37.6%. Malignancy grade and clinical stage are clearly correlated in the whole material. In incidental carcinoma, there is also a correlation between malignancy grade and histologic extension. The percentage of higher malignancy grades G II and G III increases with age. This is true for incidental carcinoma as well. The findings emphasize the prognostic significance of the grading system.