We evaluated 665 patients who had undergone TURP and 100 patients who had undergone TUIP (50 bilateral, 50 unilateral). Transurethral incision, when indicated (less than 35 gm, no middle lobe), had the following advantages: easy to perform, short operating time (39 minutes) and hospitalization (3-4 days). There was less bleeding; 2% versus 6% for TURP. The complication rate was lower: no bladder neck sclerosis for TUIP versus 2.9% for TURP; urethral stenosis: 6% for the bilateral and 0% for the unilateral incision versus 8.7% for TURP, and the incidence of retrograde ejaculation was 24% for the bilateral and 19% for the unilateral incision versus 82% for TURP. We also evaluated the disadvantages of transurethral incision: no tissue for study 4% incidental prostate cancer for TURP, limited indications, anatomic variability, less disobstructive, reoperation rate was 10% versus 11.7% for TURP, design of comparative studies deficient and no long-term follow up. The results of bilateral and unilateral incision were compared, however no statistically significant differences were observed. The bilateral incision procedure was slightly more disobstructive: 92% clinical improvement for the bilateral and 84% for the unilateral, increased flow was 6.5% for the bilateral versus 5.6% unilateral, and the reoperation rates were 2% for the bilateral and 8% for the unilateral incision procedure. However, there were less complications for the unilateral incision procedure: no stenosis for the unilateral and 6% for the bilateral, and retrograde ejaculation was 81% for the unilateral and 76% for the bilateral incision procedure. For all the foregoing reasons, we prefer to do unilateral incision of the prostate.