Interrater reliability of the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination was assessed by three neurologists experienced in the administration of this scale. Intraclass correlation coefficients indicated good-to-excellent agreement for speeded repeated movements, resting tremor, arising from a chair, and gait; moderate agreement for action tremor, rigidity, posture, postural stability, and bradykinesia; and poor agreement for speech disorder and facial immobility. Overall, these results indicate that satisfactory interrater reliability is attainable with the UPDRS motor examination.