Background: Effective post-operative analgesia is obtained by Tranversus Abdominis Plane Block and it decreases consumption of post-operative opioids significantly after abdominal surgeries. Aims: To evaluate which period is more effective for Tranversus Abdominis Plane (TAP) Block administration using Ultra sound guidance for post-operative analgesia in patients undergoing total abdominal hysterectomy. Materials and Methods: This was a prospective randomized, double blind study conducted on 70 patients between ages of 19 and 66 years, with ASA class I-II. The subjects were divided into two Groups. The TAP block was given pre-operatively to Group I patients and was given post-operatively to the Group II patients. These patients were scheduled to undergo open total abdominal hysterectomy. Both the groups received standard general anesthetic technique. In the post-operative period tramadol (20 mg/2 ml bolus intravenous and then 10 mg/ml I.V. with a five minute lock out period) was given that was controlled by the patient. Metoclopramide 10 mg I.V. 8 hourly was given as per PONV score. The Numerical Rating Scale was used to assess pain. The NRS scores were recorded at 2, 4, 6, 12 and 24 hours post-operatively. The NRS at rest, the NRS on movement and sedation score were recorded. Tramadol consumption in both groups was compared. Results: When both the groups were compared it was observed that the NRS scores at rest were significantly lower in Group 2 at 2 and 4 hours post-operatively (p < 0.05). In Group 2, the 24 hour tramadol consumption was significantly lower than that of Group 1 (p < 0.05). Conclusion: Post-operative ultrasound guided TAP Block confers significantly reduced pain scores in the early post-operative periods of TAH cases as compared to pre-operative TAP block.