The 6-month results of treatment with transurethral microwave thermotherapy (Prostalund) of 28 patients with lower urinary tract symptoms (LUTS) due to benign hyperplasia of the prostate are reported. The median International Prostate Symptom Score (I-PSS) fell from 16.5 (range 9-33) to 10.5 (range 3-30; P < 0.00005). Quality-of-life assessment improved from a median value of 4 (range 2-6) to 2 (range 1-5; P = 0.0001). In the Danish Prostate Symptom Score (DAN-PSS) the median total score fell from 20 (range 5-55) to 5 (range 0-43; P = 0.001). The median peak urinary flow increased from 10.6 to 11.5 ml/s (P = 0.20). Pressure-flow studies revealed no decrease in the median detrusor pressure at peak uroflow (PdetQmax) from 56 cmH2O preoperatively to 56 cmH2O after 6 months (P = 0.36). No change was found in postvoid residual urinary volume or in the calculated prostate volume. Complications included hematuria in most patients, urinary tract infections in 6 (21.4%) patients, and transient retention in 3 (10.7%) patients. In all, 20 (71.4%) patients responded to treatment with good symptomatic relief, but only minor changes were observed in urodynamic parameters.