Background and objective: The aim of this study was to compare the postoperative analgesic efficacy of intraperitoneal tramadol with intravenous tramadol or normal saline in patients undergoing laparoscopic cholecystectomy. Methods: Sixty-one patients undergoing laparoscopic cholecystectomy were randomized to one of three groups in a double-blind manner via coded syringes. All patients received an intravenous and an intraperitoneal injection after installation of the pneumoperitoneum and again before removal of the trocars. In the control group, all injections were with normal saline. In the intravenous tramadol group, patients received intravenous tramadol 100 mg and intraperitoneal saline. In the intraperitoneal tramadol group, patients received intravenous saline and intraperitoneal tramadol 100 mg. All patients had a standard anaesthetic. Postoperative analgesia was with morphine. Postoperatively, numeric pain scores for parietal and visceral pain, I h and 24 h morphine consumption, and adverse effects were recorded. Results: Parietal and visceral pain scores were lowest in the intravenous tramadol group during the first postoperative hour (P < 0.016 compared with control). The delay until the first analgesic administration was longest in the intravenous tramadol group (median 23 min, range 1-45), when compared with the intraperitoneal tramadol group (10, 1-120 min, P = 0.263) or with the control group (1, 1-30 min, P = 0.015). One-hour morphine consumption was significantly lower in the intravenous tramadol group (mean +/- SD; 3.4 mg +/- 2.5) and in the intraperitoneal tramadol group (4.4 +/- 4.3 mg) compared with the control group (6 +/- 2 mg) (P = 0.044). There was no difference between the three groups regarding pain scores, morphine consumption and incidence of shoulder pain or adverse effects at 24 h. Conclusion: Intravenous tramadol provides superior postoperative analgesia in the early postoperative period after laparoscopic cholecystectomy compared with an equivalent dose of tramadol administered intraperitoneally and with normal saline in patients undergoing laparoscopic cholecystectomy.