The number of silver-stained nucleolar organizer regions (AgNORs) and the status of nucleoli were studied in biopsies from 10 cases of normoglandular prostatic tissue and the findings were compared with the results obtained for 10 cases of hyperplastic prostatic tissue (BPH) and 74 cases of prostatic carcinoma of various grades of malignancy. There was an increase in the number of AgNORs detected between the grade of malignancy found in highly versus poorly differentiated carcinomas of the prostate. Furthermore AgNOR values differed significantly among the groups compared (P < 0.001). The nucleolar status confirmed these differences. In addition, the significantly different survival of patients suffering from prostatic carcinomas support our idea of subdividing GII carcinomas into group IIa (low risk) and group IIb (high risk). This subgrading implies the possibility of preoperatively identifying patients with a prostate carcinoma of high malignancy within the GII carcinoma group.