Transurethral incision of the prostate and bladder neck (TIPBn) was compared with transurethral resection of the prostate (TURP) followed by bladder neck incision in the treatment of 22 patients with outflow obstruction caused by a small prostate adenoma (below 15 gm). Eleven patients underwent TIPBn and another 11 TURP. An evaluation of the urodynamic findings and subjective symptoms was undertaken before the operation and 3 months afterwards. Urodynamic findings were evaluated, based upon uroflowmetry, i.e., in terms of maximum flow rate, average flow rate, voiding time, initiation time and residual rate. All patients in the TIPBn group revealed an improvement in every urodynamic parameter (MFR: from 6.1 to 10.8 ml/sec, AFR: from 3.1 to 5.8 ml/sec, Voiding time: from 95.5 to 24.2 sec/100 ml, Initiation time: 34.3 to 10.2 sec, Residual rate: 31.6 to 17.8%, in mean value). Ten out of the 11 in the TIPBn group subjectively considered the result to be good. The improvements in the urodynamic parameters in the TIPBn group were statistically comparable to those in the TURP. The improvements in voiding time and initiation time, however, tended to be much better in the TIPBn group. We conclude that TIPBn can be the operation of choice in the treatment of outflow obstruction caused by a small prostate.