We studied the effect and temporal profile of deep brain stimulation (DBS) of the globus pallidus and subthalamic nucleus on the motor signs of Parkinson's disease (PD). Four patients with bilateral deep brain stimulators of the globus pallidus and four patients with bilateral deep brain stimulators of the subthalamus were studied while taking no medication and at 15 and 30 minutes and 1, 2, 4, and 6 hours after turning stimulation on. An immediate (15 minutes) and sustained (6 hours) benefit was observed for all the motor manifestations of PD for both stimulation sites. Deep brain stimulation of the globus pallidus and subthalamus is highly effective in reducing all the cardinal motor features of PD.