In 268 patients seen for sterility, sexual impairment or suspected prostatitis symptoms, first and midstream urine fractions, prostatic secretion and post-massage urine cultures as well as semen cultures and exfoliative cytologies of the first urine fraction and prostatic secretion were performed. Gram-positive bacteria were isolated in 160 cases. Of these, 111 (69.3%) had significant cultures (Meares and Stamey criteria). Nevertheless, when we repeated the study without previous therapy, the results could not be confirmed. This shows that Gram-positive bacteria do colonize urethra and/or prostatic ducts, but are not responsible for prostatic infection.