The prostatic adenocarcinoma is one of the most frequent malignant tumors of men over 50 years of age. It is distinguished by agressive clinical course and heterogeneous multifocal hystomorphologic changes. PSA is the most reliable serum marker in diagnostics and observation of prostatic carcinoma and gleason's system of tumor-diferentiation grading is generally accepted way of determining the hystologic grade. Gleason's system is correlated with serum levels of PSA and with biological behaviour of the tumor. We presented 40 patients with verified ACP in whom the level of serum PSA, gleason's grade and score were compared. Highly significant correlation was found between serum level of PSA and the differentation grade of the tumor - Gleason's grade and score. Combination of PSA parameters and Gleason's score enables correct estimation of tumor's behaviour and correct therapeutic protocole.