BACKGROUND: Propofol is a rapidly acting intravenous anesthetic agent used for the induction of anesthesia with a low incidence of side effects. But propofol has a high incidence of pain during intravenous injection, and many methods have been used to minimize the incidence and severity of this pain. The aim of this study was to compare the use of thiopental and lidocaine mixed with propofol for the reduction of pain during the injection of propofol. METHODS: Sixty healthy ASA physical status I or II patients scheduled for general anesthesia were randomly divided into three groups. Each patient received mixed propofol solution (normal saline 1 cc, thiopental 0.5 mg/kg, lidocaine 0.5 mg/kg) via 20 G angiocatheter inserted at the antecubital fossa. The assessment of pain was done at the induction of anesthesia and at the recovery room. The severity of pain was classified as none, mild, moderate, and severe. RESULTS: The severity and incidence of pain diminished significantly in the thiopental group and the lidocaine group compared with control group at the induction of anesthesia (p<0.05), and there was no significant difference between the thiopental and the lidocaine group. Recall of pain during intravenous injection at the recovery room has no significant difference among three groups. CONCLUSIONS: Mixd administration of thiopental or lidocaine could significantly reduce the severity and incidence of pain for intravenous injection of propofol.