PURPOSE: Open prostatectomy have been considered primarily when the prostate volume is large(e.g. >75 cc). However, with the development of surgical skills and instruments, transurethral resection of prostate(TURP) can be an alternative. We assessed the feasibility of TURP for patients with large benign prostatic hyperplasia(BPH) by comparing the efficacy of TURP with that of open prostatectomy, retrospectively. MATERIALS AND METHODS: From January 2000 to March 2005, a total of 54 BPH patients with a prostate larger than 75 cc in volume on transrectal ultrasonography underwent surgery in our hospital. Among these patients, 26 patients underwent TURP(Group T) and 28 patients underwent suprapubic prostatectomy(Group O). Group T was subclassified Group T-1(prostate volume 75~100 cc, n=12) and T-2(prostate volume > or = 100 cc, n=14). In the same way, Group O was divided into Group O-1(n=9) and O-2(n=19). Operative time, time to catheter removal, hospitalization, and complications were compared. Operative results were evaluated at 6 months postoperative by comparing preoperative and postoperative International Prostate Symptom Scores(IPSS), maximal flow rates(Qmax) and post void residual(PVR). RESULTS: Preoperatively, there were no significant differences in IPSS, Qmax or PVR between Groups T-1 and O-1 or between Groups T-2 and O-2. Although delta IPSS, delta Qmax and delta PVR improved in Group O-2 more than T-2, there were no statistically significant differences between Group T-1 and O-1. The mean operative time, time to catheter removal, and hospitalization were shorter in Group T than Group O. Postoperative complication rates were similar in the T and O groups. In Group T, there was no TUR syndrome, but urinary tract infections and urethral stricture were more common than in Group O. However, Group O had higher incidences of severe complications, including wound infection or bleeding requiring transfusion. CONCLUSIONS: Open prostatectomy is commonly considered when prostate volume is greater than 75 cc. If enough resection is performed, TURP is a valuable non-invasive surgical method with respect to absence of incision, effective symptom improvement, and short hospitalization in symptomatic BPH patients who have prostate volume less than 100 cc.