A case is described of a patient with levodopa responsive parkinsonism, dyskinesia, and off periods who underwent bilateral deep brain stimulation of the subthalamic nuclei (DBS-STN) with good result. As the disease progressed, the patient fit diagnostic criteria for progressive supranuclear palsy parkinsonism (PSP-P). Benefit of DBS for the parkinsonian phenomena is still apparent 4 years later. That DBS-STN provided targeted symptom relief in this unusual patient suggests that the parkinsonism of PSP-P and that of Parkinson's disease (PD) may share a common pathophysiologic mechanism. The presence of dystonic features in this illness raises the possibility that the globus pallidus might also have been an effective target.