Anhedonia, a core symptom of depression, correlates with motor alterations in major depressive disorder and has been assumed to be frequent in depressed patients with Parkinson's disease (PD). In the present study, the authors assessed for the first time frequency of anhedonia in patients with idiopathic Parkinson's disease (N = 657) and the relationship of anhedonia and parkinsonian motor deficits during treatment with pramipexole. Mild depression was present in 47% of the patients and moderate to severe depression in 22%. Anhedonic individuals included 45.7% of all patients and 79.7% of depressed Parkinson's disease patients. Anhedonic Parkinson's disease patients had greater motor deficits, restrictions in activities of daily living, and depression compared to nonanhedonic patients. Frequency of anhedonia and depression was significantly reduced during treatment with pramipexole. Future studies should further investigate antianhedonic efficacy of dopamine agonists including pramipexole in depressed patients with Parkinson's disease.