Introduction: To date various modalities of treatment are available ranging from opiods, multimodal therapy and Non-steroidal Anti-inflammatory Drugs (NSAIDs). Still NSAIDs are popular choice as they are easy to administer and their effects can easily be monitored. Aims: The aim of the present study is to “Compare intramuscular administration of Injectable Aceclofenac with Injectable Diclofenac in Post-operative Analgesia in patients undergoing Laparoscopic Abdominal Surgeries the efficacy and duration of action. Materials and Methods: It is a double blind prospective randomized study was conducted on 50 patients divided into two Groups of 25 each. Group I aceclofenac, Group II Diclofenac. Study done to compare the relative efficacy of injection aceclofenac and injection Diclofenac by intramuscular route for post-operative analgesia in patients undergoing laparoscopic abdominal surgeries. Results: The quality of analgesia with injection aceclofenac is better than that of injection Diclofenac post-operatively. Both the Groups exhibited hemodynamic stability. Incidence of rise inpulse rate and MAP in the post-operative period was higher with injection Diclofenac than Injection Aceclofenac. Injection aceclofenac in our study scores over injection Diclofenac in providing better quality of analgesia injection consistent with the pharmacokinetic profile of all the patients in Group II Diclofenac required for an additional dose of analgesic after 8 hours. Early ambulation was possible in both the Groups. The analgesia with injection aceclofenac is sustained over longer periods of time upto 24 hours. A single dose is required. Conclusion: We conclude that there is definite place for long acting NSAIDs like Injection Aceclofenac 150 mg/3 ml in the post-operative analgesia for patients undergoing laparoscopic abdominal surgeries in view of its good quality of analgesia, sustained and prolonged duration action upto 24 hours and better gastrointestinal tolerance.