BACKGROUND: Pain on injection of propofol is a common problem, the cause of which remains unKnown. We evaluated the optimum time of a tourniquet with intravenous lidocaine, to decrease the intensity of pain during intravenous propofol injection. METHODS: In 72 patients undergoing general anesthesia, we subdivided all patients into 4 groups. Patients in group 1 (n = 18) received propofol only (1 mg/Kg IV) without a tourniquet, patients in group 2 (n = 18) received 1% lidocaine 20 mg IV with an upper arm tourniquet inflated to 50 mmHg applied for 1 minute followed by propofol (1 mg/Kg IV). We applied a tourniquet to patients in group 3 (n = 18) and 4 (n = 18) for 3 minutes and 5 minutes respectively. The intensity of pain along the forearm was classified in 4 degrees (none, mild, moderate, severe) by the patients and the observer simultaneously. The mean arterial pressure and heart rate were recorded before injection and at the time when the patient complained of pain. RESULTS: All groups were similar in age, sex, weight and height. The group with the tourniquet applied for 5 minutes followed by a lidocaine injection showed the lowest intensity of pain. However, between the group with 3 minutes and 5 minutes, the difference of the pain score was not statistically significant. CONCLUSIONS: We conclude that intravenous lidocaine administered after a tourniquet has been inflated to 50 mmHg for 3 minutes before propofol injection attenuates profoundly the pain associated with intravenous propofol injection.