We treated 229 cases of chronic prostatitis (bacterial in 29, non-bacterial in 200) and 238 cases of prostatitis-like syndrome and evaluated the clinical efficacy. Clinical efficacy was seen in 77.3% of the chronic prostatitis cases (82.8% bacterial, 76.5% non-bacterial) and 53.8% of the prostatitis-like syndrome cases, with a statistical difference between these two types of disease (p less than 0.01). Treatment included chemotherapy, anti-inflammation agents and minor tranquilizers. None of them were effective against the prostatitis-like syndrome. On the other hand, combination usage (chemotherapies and anti-inflammation agent) was satisfactory on chronic bacterial prostatitis. Also on chronic non-bacterial prostatitis, chemotherapy was significantly effective (p less than 0.05%). Chemotherapeutic effectiveness against chronic prostatitis (both bacterial and non-bacterial) was high with sulfamethoxazole-trimethoprim, tetracyclines, cephalosporins, nalidixic acid and penicillins in this order. There was no difference among these drugs. Prostatic massage was generally effective especially for chronic non-bacterial prostatitis (p less than 0.05) and prostatitis-like syndrome (p less than 0.01). Light psychological treatment was significantly effective toward some cases of prostatitis-like syndrome with strong psychosomatic factors (p less than 0.01).