From 1983 to 1991, 13 patients were identified with a clinical radiologic association characterized by acute or persistent neurologic dysfunction and bilateral lesions in the basal ganglia region demonstrated by ultrasound, computed tomography, or magnetic resonance imaging. Initial clinical manifestations of this group of patients were characterized by extrapyramidal signs (i.e., dystonia 9, hypotonia 2, athetosis 1, rigidity 1), altered state of consciousness in 5, and seizures in 3. The outcomes of most of these patients were poor: 10 had motor sequelae, 9 cognitive impairment, and 4 died. The outcomes of 2 patients, however, were much better than what was expected from the initial presentation. Based on current and previous reports, the diagnostic approach and classification of patients with neurologic dysfunction and bilateral striatal lesions are presented. © 1993.