The objective of the Post Marketing Surveillance Study is to investigate the use of the non-ergot dopamine agonist piribedil (trade name: CLARIUM) in mono- and combination therapy in patients with Morbus Parkinson. Neurologists in private practices in Germany should document the safety and course of the disease/change of parkinsonian symptoms during stabilisation on, or change over from other dopamine agonist treatment under routine conditions. Piribedil should be prescribed according to its marketing authorisation.