Objective: To assess the effect of transrectal ultrasound guided prostatic nerve blockade on the discomfort associated with systematic biopsy of the prostate. Methods: 73 patients receiving systematic 13 cores biopsy of the prostate were randomized into two groups. Group A(37 cases) received an injection of 5 ml 1% lidocaine into the prostatic neurovascular bundles on each side at the base of the prostate under ultrasound guidance and group B(36 cases) received 5 ml saline injection (0.9% sodium chloride) at the same site. Pain during biopsy was assessed by using a 10-point linear visual analog score (VAS) immediately after the biopsy. Results: The mean pain scores during transrectal prostate biopsy were significantly lower in group A than group B(1.1±0.6 versus 5.9±3.1, t=4.81, P＜0.01). During this study no patient in either group had any adverse effect from the injection. Conclusion: Transcrectal ultrasound guided prostatic nerve blockade is a safe and efficacious method for providing satisfactory anesthesia in transrectal prostate biopsy. We recommend its routine administration in all patients during this procedure.