The purpose of this study was to compare the effect of intravenous ketamine and metochlopramid before induction of anesthesia on postoperative pain and analgesic requirements. In this double blind clinical trial, 86 ASA1, 2 patients who were candidates for lower abdominal surgery, were enrolled. The patients with severe bleeding and those who needed blood transfusion were excluded. The eligible patients were randomly assigned to receive metoclopramide, 10 mg, or ketamine, 0.3 mg/kg, intravenously before induction of anesthesia. Score of pain, amount of opioid consumption in recovery and first 24 hours, and postoperative complications such as nausea and vomiting, postoperative ondansetron consumption, irritability, and psychological problems record were measured and compared between groups.