The intraoperative use of opioid analgesics decreases the volatile anesthetic requirement and provides for pain relief in the early postoperative period. In a randomized double-blind, placebo-controlled study involving 95 ASA physical status 1 or 2 children (ages 5–15 yr) undergoing general anesthesia for elective operations, we compared postoperative analgesia following the intraoperative intravenous (iv) administration of ketorolac, a nonsteroidal antiinflammatory drug or morphine, an opioid analgesic. After induction of general anesthesia and before the start of the surgical procedure, children received equal volumes of saline, morphine (0.1 mg · kg-1, iv) or ketorolac (0.9 mg · kg-1, iv). Postoperative pain was evaluated by the child using a 10-cm linear visual analog scale (VAS) and by a blinded observer using both a VAS and an objective pain scale (OPS) in the postanesthesia care unit (PACU). There were no statistically significant differences in the VAS and OPS scores in the PACU or in the postoperative analgesic requirements in children receiving morphine or ketorolac. The placebo group had a significantly higher VAS and OPS score and required earlier and more frequent analgesic therapy in the PACU compared to the two analgesic groups. Patients receiving ketorolac had less postoperative emesis than those receiving morphine. We conclude that ketorolac (0.9 mg · kg-1) is an effective alternative to morphine (0.1 mg · kg-1) as an iv adjuvant during general anesthesia, and in the dose used in this study, is associated with less postoperative nausea and vomiting in children.