OBJECTIVE: To compare the efficacy of the combined intra-rectal lidocaine gel and peri-prostatic nerve block versus caudal block for pain relief during trans-rectal ultrasound scan guided prostate biopsy (TRUSP). MATERIALS AND METHOD: A prospective randomized study of 112 patients; 56 patients in each arm of the study. All the patients had a three-day bowel preparation, prophylactic antibiotics, general evaluation of the prostate with trans-rectal ultrasound scan (TRUS) and 10 core biopsies. Comparative analysis was made of the pain scores, complication and failure rates between the two arms of the study. Pain scores were assessed using the numerical rating scale (during anaesthesia, TRUS probe insertion into the ano-rectum, biopsy needle puncture of the prostate and one hour after biopsy). RESULTS: The age of the study population ranged from 45-89 years with a mean of 64.3 + 9.0, the mean age of the combined peri-prostatic nerve block (cGPNB) and caudal block (CB) arms were 65.0 + 9.2 and 63.6 +8.8 years respectively. The mean prostate specific antigens (PSA) were 23.6 + 36.0 and 18.5 + 25.4 ng/ml for cGPNB and CB respectively. Prostate volumes were 79.0 + 50.7 and 67.3 + 44.0 mls for cGPNB and CB arms respectively. There was no significant difference in age, PSA and prostate volume between the two arms of the study. Both cGPNB and CB produced satisfactory pain relief at all stages of the procedure, nevertheless, CB produced significantly more pain relief than cGPNB during TRUS probe insertion into the ano-rectum (0.3 + 0.8 versus 1.1+ 1.3) and during needle puncture of the prostate (0.9 + 1.9 versus 1.3 + 1.9) with P-value of 0.001 and 0.015 respectively. Comparative analysis of anaesthesia-related complications showed that dizziness was significantly commoner (p = 0.02) in the cGPNB (76.6 versus 23.5) whereas paraesthesia/paraparesis occurred only in the CB arm. Biopsy–related complications were similar in both arms of the study. The cGPNB had a lower but statistically insignificant anaesthesia failure rate. CONCLUSION: The study revealed that both anaesthesia methods produced satisfactory pain relief at all stages of prostate biopsy. However, CB was found to produce significantly superior pain relief during probe insertion and during biopsy of the peripheral zones of the prostate. Transient paraparesis/paraplegia and paraesthesia occurred only in the CB arm; whereas dizziness was significantly commoner in the cGPNB arm. Other complications, as well as failure rate were similar in both arms of the study.