Purpose: We wanted to compare the treatment outcome, safety, efficacy and complications of transurethral resection of the prostate (TURP), interstitial laser coagulation (ILC), transurethral needle ablation (TUNA) and transurethral ethanol ablation of the prostate (TEAP) for the treatment of benign prostatic hyperplasia (BPH). Materials and Methods: In this prospective, randomized study, a total of 403 patients with symptomatic BPH were treated by TURP, ILC, TUNA or TEAP from January 1998 to December 2002. ILC was performed using the Indigo 830e LaserOptic TM System with a specially designed interstitial thermotherapy light guide, TUNA was performed using the VidaMed TUNA System and TEAP was performed using the Prostaject TM device. The treatment outcomes were evaluated at 3 months, 6 months and 1 year with the International Prostate Symptom Score (IPSS), the prostate volume, the maximal urinary flow rate (Qmax), the post-void residual urine (PVR), and the quality of life (QoL) assessment score. Results: All the patients in the four groups showed significant improvement for all the parameters. After 1 year, the four groups showed significant improvement in the clinical and voiding parameters (IPSS, Qmax, PVR, prostate volume and QoL). Our results did not show significant differences in the IPSS, prostate volume and QoL among the four groups. However, the TURP group showed a higher Qmax, and the TEAP group showed a less reduced prostate volume than the other groups during the follow-up period (p 0.05). The period of hospital admission showed no significant difference between the ILC, TUNA and TEAP groups, but the TURP group showed a longer hospital admission period compared to the other groups. The TURP group was markedly associated with more complications than the other groups. Conclusions: These early results indicate that ILC, TUNA and TEAP are safe, effective and useful alternative therapies to TURP for the patients with symptomatic BPH. (Korean J Urol 2006;47:13-19) ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ