A number of studies have shown that Chlamydia trachomatis bacteria are important pathogens in urogenital tract infections, such as acute urethritis, acute epididymo-orchitis in male patients and pelvic inflammatory disease in female patients. We confirm a previously reported association between Chlamydia trachomatis and prostatitis. We report on 6 patients with definitive confirmation via tissue culture and an immunofluorescent technique. The results demonstrate that chlamydial prostatitis occurs in patients with nonbacterial disease. Efforts should be made to detect and eradicate the organisms from the prostate.