Pulmonary dysfunction was investigated in fifty-eight Parkinson's patients. Clinical disability was assessed by the Unified Parkinson's Disease Rating Scale. Pulmonary dysfunction was studied by spirometry with flow-volume loops, body plethysmography with lung volumes computation and maximal inspiratory and expiratory static mouth pressures. Forced vital capacity (FVC), forced expiratory volume in 1 min (FEV1), FEV1/FVC% and arterial PO2 and PCO2 were significantly below normal values. Residual volume (RV) and total rows were above normal values. Thirty-six had upper airway obstruction as judged by inspiratory flow peaks (PIF) < 3 l/s and FEV1/PEF (expiratory flow peak) > 8.5 l/min and MEF50/MIF50 > 1. Eighteen patients had a central (FEV1 < 80% and FEV1/FVC% < 80% of normal values) or peripheral (maximal expiratory flow between 75% and 25% of FVC and maximal expiratory flow after expiration of 50% below 70% of normal values) obstructive pattern. Sixteen patients had a restrictive dysfunction as judged by a total lung capacity < 85% or FVC < 80% with FEV1/FVC% > 80%. Sixteen patients had air trapping (RV > 120% and RV/TLC > 40%) and seven patients had lung insufflation (TLC > 120%). Rigidity, Rx signs of cervical arthrosis and limitations for passive movement of neck were higher in patients with central or peripheral airway obstruction. Bradykinesia and Rx signs of dorsal arthrosis was higher in patients with upper airway obstruction. Restrictive dysfunction was not related to tremor, rigidity or bradykinesia. The present data support the hypothesis that Parkinson patients present a high risk for pneumologic disturbances. These pulmonary dysfunctions are induced by the simultaneous action of a group of factors including the degree of bradykinesia or rigidity and the musculoskeletal limitations of vertebral column probably induced by chronic anomalous posture.