PURPOSE: We evaluated the safety and efficacy of intrarectal administration of anesthetic agent for transrectal prostate biopsy. MATERIALS AND METHODS: For a double-blind prospective trial, 100 men undergoing transrectal prostate biopsy were randomized into three groups using an established list. In the control group (n=36), 40mL of normal saline was administered transrectally 10 min before the procedure. The lidocaine group (n=31) and the benzocaine group (n=33) were give 40 mL of 1% lidocaine and 0.3% benzocaine, respectively. Patients were asked to score the severity of the pain expected before and after the biopsy procedure using a self-administered verbal rating scale. Pain was assessed using a 10-point linear visual analog scale. RESULTS: The median pain score expected before the transrectal prostate biopsy was 6.7+/-0.3, 7.1+/-0.2, and 6.7+/-0.3 in the control, lidocaine, and benzocaine group, respectively. The median pain score during the biopsy was 6.1+/-0.3, 5.8+/-0.3 (P<0.05), and 5.9+/-0.4 in the control, lidocaine, and benzocaine group, respectively. Ninety seven percent of the control group, 100% of the lidocaine group, and 91% of the benzocaine group complained of severe and bothersome pain, with a score of 5 or greater during the biopsy. No adverse events were noted. CONCLUSIONS: Intrarectal administration of anesthetic agent is a simple, safe, and efficacious method of providing satisfactory anesthesia in patients undergoing transrectal prostate biopsy. We recommend 1% lidocaine solution in the patients to perform transrectal prostatic biopsy.