Over the past 20 years, tritiated radioligand receptor binding has been used to study the relationship between dopamine receptor binding and various movement disorders, in particular Parkinson disease. More recently, in vivo imaging techniques like positron emission tomography and single photon emission computed tomography have been used to study the dopaminergic system in these disorders. This review describes the data that have been obtained using in vivo and in vitro measurements of the dopaminergic system in movement disorders, and examines the relationship between them. The contribution of these techniques to clinical management is described.