In order to decrease complications of local anesthetic, early detection of intravascular injection of local anesthetics is inevitable. However, heart rate response to intravenous(iv) epinephrine test dose injection may result in false-positive or false-negative result. Besides, glycopyrrolate pretreatment may enhance heart rate response to epinephrine test dose. We allocated randomly 30 ASA physical status 1 and 2 patients to two groups, to receive glycopyrrolate 0.2 mg(n=15) or same volume of saline(n=15). Five minutes after glycopyrrolate pretreatment, patients received iv test dose of 2% lidocaine 3 ml with epinephrine 15 pg at a rate of 1 ml/sec. Two groups were similar with respect to basal heart rate. Heart rate and mean arterial pressure increased significantly in both groups at 1, 2, 3 and 4 minutes after epinephrine test dose injection. After 5 minutes, heart rate and mean arterial pressure normalized in both groups. Thus we might suggest that glycopyrrolate pretreatment has no influence on the sensitivity of the test dose containing 2% lidocaine 3 ml and epinephrine 15 ug to detect intravascular injection of local anesthetics.