Fourteen young and sexually active patients with chronic abacterial prostatitis who failed to respond to conventional medical therapy underwent four 60 minute sessions of local prostatic hyperthermia. Calculated prostatic temperature was 42 +/- 0.5 degrees C. Analysis of seminal plasma was performed pre- and postoperatively and included: number, motility, and morphology of spermatozoa; zinc, citric acid, D-fructose, and free testosterone content. Preoperative semen analysis was normal in five patients and abnormal in nine. Morphodynamic and biochemical patterns of seminal plasma were not significantly altered by thermotherapy. Local prostatic hyperthermia can be safely used in patients with chronic abacterial prostatis not responding to conventional medical therapy and desiring to preserve their reproductive potential.