The authors studied a 1-year effect of transurethral microwave thermotherapy (TUMT) using the PROSTCARE apparatus (Bruker Spectrospin Wissembourg, Frace) on 35 patients with symptomatic benign prostatic hyperplasia (BPH). The device is equipped with a unique non-invasive system "radiometry" for the measurement of the intraprostatic temperature to regulate the microwave emission power and to eliminate classic surface controls. All of the 35 patients received a single thermotherapy session (60 minutes), the average intraprostatic temperature was 43.6 +/- 1.2 degrees C (mean +/- SD) and the average power output was 43.9 +/- 4.1 Watt. The clinical effects were evaluated at 2 months, 6 months and 1 year after TUMT by a specially designed score scale for subjective symptoms and objective findings as compared with the pretreatment score. Assuming that more than a 25% reduction of the total score indicates "effective", 71.4%, 71.4, and 48.6% of the treatments remained effective at 2 months, 6 months, and 1 year after TUMT, respectively. The maximum prostatic urethral pressure profile decreased from 64.1 +/- 17.1 to 51.7 +/- 15.6 cmH2O (p < 0.05) at 2 months after TUMT. The thermotherapy by PROSTCARE is effective in approximately 50% of patients at least 1 year and there were no major complications associated with TUMT during the follow up period.