BACKGROUND: Propofol, a new intravenous anesthetic agent, is now used for brief operation and day surgery for its rapid recovery and controllability. Propofol, rapid acting sedatives hypnotics, is known to no analgesic effect. This study was taken to evaluate the analgesic effect of propofol, compared to those of fentanyl. METHODS: Forty patients (ASA physical status 1, 2) scheduled for surgery of short duration (within 1 hour) were randomly allocated into two groups. Induction of anesthesia was performed by injection of thiopental (5 mg/kg) and succinylcholine (1 mg/kg) and ventilated with O2-N2O (50%) after endotracheal intubation. Maintenance of anesthesia was performed by vecuronium (1 mg/kg) and continuous infusion of propofol (group I) or fentanyl (group II). RESULTS: There was no significant differences in systolic and diastolic blood pressure in both groups. In heart rate, there was significant difference at preincision and postincision between two groups. Time to extubation (4.5 +/- 4.6 vs 6.3 +/- 4.6 min), time to eye open (7.5 +/- 7.1 vs 6.6 +/- 5.4 min), time to complain pain after stop dropping at recovery room (30.5 +/- 8.0 vs 35.5 +/- 17.9 min), the average flow rate of drugs (6.0 +/- 2.2 mg/kg/hr vs 6.7 +/- 2.4 microgram/kg/hr) has no significant difference between two groups. CONCLUSIONS: A single continuous infusion of propofol is applied as one of general anesthesia methods with O2-N2O, muscle relaxants. Propofol has a appropriate and similar analgesic effect compared with fentanyl in operation of little hemodynamic changes and short operation, and rapid recovery compared with fentanyl.