Molecular imaging with PET offers a broad variety of tools supporting the diagnosis of movement disorders. The more widely applied PET imaging techniques have focused on the assessment of neurotransmitter systems, predominantly the pre- and postsynaptic dopaminergic system. Additionally, PET imaging with [(18) F]fluorodeoxyglucose has been extensively used to assess local synaptic activity in the resting state and to highlight local changes in brain metabolism accompanying changes in neural activity in movement disorders. PET imaging has provided us with diagnostic agents as well as tools for evaluation of novel therapeutics, and has served as a powerful means for revealing in vivo changes at different stages of movement disorders and within the course of an individual patient's illness.