The basal ganglia are implicated in a number of disorders including neurodegenerative motor diseases such as Huntington's and Parkinson's disease, as well as psychiatric disorders such as schizophrenia and obsessive compulsive disorder. In recent years, a great deal of effort has been focused on determining the basal ganglia circuitry that underlies normal behavior, as well as many of these syndromes. This has led to a detailed understanding of both the normal and pathophysiological flow of information through the basal ganglia, and has provided the opportunity to begin developing novel pharmacological methods of intervention by targeting neuromodulatory receptors with in the basal ganglia circuit. One group of receptors that holds much promise for several basal ganglia disorders is the metabotropic glutamate receptors. Data from behavioral, neurochemical, neuroanatomical and electrophysiological studies has begun to reveal the functional roles that the metabotropic glutamate receptors play in modulating the basal ganglia circuit, and suggests that compounds selectively targeting these receptors may provide novel therapies for a variety of disorders including Parkinson's disease, addiction, and epilepsy.