The investigation included 98 patients with the level of prostate specific antigen (PSA) of blood serum from 0 to 10 ng/ml and with the diagnosis confirmed by the systemic 12-points prostate biopsy. The data obtained clearly show that the PSA density of the transition zone is a potentially true predictor for the early prostate cancer diagnosis in patients with low and middle PSA level (from 0 to 10 ng/ml). When the threshold level of the PSE density in the transition zone is 0.35 ng/ml/cc, its sensitivity and specificity are higher than these indices for the PSA density.