Serum levels of prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA) were measured in 78 patients with benign prostate hyperplasia and compared with both the gland weight and the glandular component of prostatic tissue. Both PAP and PSA were significantly higher where prostate was heavier; however, we could not find a consistent factor which could correlate weight increase to marker levels. PSA tended to be higher when glandular component was more expressed. From the present findings we conclude that in patients with prostate cancer, PAP and PSA serum levels should be investigated considering also the benign components of prostate gland.