Propofol has a high incidence of pain with injection, particularly into small veins. We sought to determine whether concomitant administration of lidocaine could prevent this pain. In a randomized doubleblind trial, 368 women were allocated to one of four groups to receive 19 mL of propofol mixed with either 1 mL of 0.9% saline, 1 mL of 0.5% (5 mg) lidocaine, 1 mL of 1% (10 mg) lidocaine, or 1 mL of 2% (20 mg) lidocaine. The pain of injection was scored as none, mild, moderate, or severe. There was a significant reduction in the overall incidence of pain from 73% with saline to 32% with 20 mg of lidocaine. A highly significant negative dose-response relationship between the dose of lidocaine and the severity of pain was demonstrable, both at induction of anesthesia and as recalled in the recovery room (P < 0.001 for both). Lidocaine (20 mg IV) will significantly reduce the incidence and severity of pain with propofol injection, but about 6% of patients will still suffer unpleasant pain if the dorsum of the hand is used.