Study Objective To compare the effect of intraperitoneal bupivacaine and lidocaine on reducing pain after diagnostic laparoscopy. Design Randomized, double-blind, placebo-controlled study (Canadian Task Force classification I). Setting University teaching hospital. Patients One hundred thirty-four women with unexplained infertility. Intervention Diagnostic laparoscopy with intraperitoneal administration of bupivacaine or lidocaine. Measurements and Main Results Patients were randomized into one of four groups. In group A, at the end of laparoscopy 0.125% bupivacaine 30 ml was instilled into the pelvic cavity and the same dose was instilled over the diaphragmatic vault. Groups B and C received the same volume of 5% lidocaine and normal saline, respectively. Group D received no intraperitoneal agent. The verbal pain scale questionnaire was used to assess postoperative pain. Pain scores 2 and 24 hours post operatively were significantly lower for group A than for groups B and C (p = 0.0001). Scores in group B were also significantly lower than those in groups C and D (p = 0.0001). Women in group A required less additional analgesia than those in the other groups. Conclusion Compared with lidocaine and placebo, intraperitoneal bupivacaine significantly decreased postoperative pain, and this effect was long lasting.