BACKGROUND:: Deep brain stimulation has generated sustained improvement in motor function for patients with dystonia, but the long-term impact of subthalamic nucleus stimulation on dystonia has not been elucidated. METHODS:: Patients with primary dystonia underwent bilateral subthalamic nucleus stimulation and were evaluated with the Burke–Fahn–Marsden dystonia rating scale and the Medical Outcomes Study 36-item Short-Form General Health Survey at baseline and 1 month, 1 year, and 3 to 10 years postoperatively. RESULTS:: Improvements in motor function according to the Burke–Fahn–Marsden dystonia rating scale at 1 month, 1 year, and 3 to 10 years of stimulation were 55%, 77%, and 79%, respectively. The quality of life improved after 1 month of stimulation (P < 0.001), progressed within 1 year (P < 0.001), and then remained stable. Disease duration was negatively correlated with an improvement in motor function. CONCLUSIONS:: Our results demonstrate that the subthalamus is an alternative to the globus pallidus internus as a target for deep brain stimulation to treat primary dystonia. © 2013 International Parkinson and Movement Disorder Society