Parkinson's disease is an idiopathic, slowly progressive disorder of the central nervous system characterized by resting tremor, muscular rigidity, slow and decreased movement (bradykinesia), and postural instability. In the United States, Parkinson's disease is the fourth most common neurodegenerative disorder in the elderly, affecting an estimated half a million people. Oral health care providers can expect to be called upon to care for patients with this progressively debilitating disease. To provide competent care to patients with Parkinson's disease, clinicians must understand the disease, its treatment, and its impact on the patient's ability to undergo and respond to dental care.