This article is a review of autonomic dysfunction in idiopathic Parkinson's disease (iPD), as well as the clinical features of a specific form of PD, i.e. autonomic failure (AF) with PD, and is based mainly on the results obtained from our recent studies. Since James Parkinson's original discription, the definition of autonomic dysfunctions in iPD and their clinical characteristics have undergone changes. Autonomic dysfunction is considered to be uncommon and rarely severe on one hand, while not infrequent but not as severe as in Shy-Drager syndrome on the other hand. AF with PD is characterized by severe orthostatic hypotension, postprandial hypotension, supersensitivity to noradrenaline, low or absent uptake of m-[123I]iodobenzylguanidine scintigraphy of the limbs, and preserved arginine vasopressin response to head-up tilt, suggesting a postganglionic sympathetic lesion resembling pure AF (PAF). On the other hand, reduced cortical glucose metabolism in positron emission tomography study may indicate that AF with PD has diffuse nervous system lesions resembling diffuse Lewy body disease.