One hundred patients with benign prostatic hypertrophy (BPH) were randomized to transurethral incision (TUIP) or transurethral resection of the prostate (TURP). The average prostate weight before operation was not more than 30.0 g. Indications for the operations were based on the disease history, physical examination, digital rectal examination, laboratory values, and pressure-flow examination. All operations were performed with patients under spinal anesthesia. TUIP was performed with a Collins knife, and TURP was performed with a resectoscope. Follow-up was performed 24 months after the operations. After treatment there were statistically significant daytime and nocturnal reduction in voiding frequencies of 2.9 and 1.7, respectively, after TUIP, and 2.0 and 1.5 after TURP. In both groups, there occurred significantly better maximal flow rate from 7.6 mL/s to 16.9 mL/s in group I and from 6.9 mL/s to 17.6 mL/s in group II. The mean values of linearized passive urethral resistance relation in both groups significantly decreased from 3.6 ± 0.6 to 1.0 ± 0.5 after TUIP and from 3.9 ± 04 to 1.4 ± 0.5 after TURP. The TUIP procedure is effective and safe for patients with a small number of complications. Neurourol. Urodynam. 21:112–116, 2002. © 2002 Wiley-Liss, Inc.