Beck depression inventory (BDI-1A) is the gold standard screening tool for Parkinson's disease (PD) depression, but as a result of its complexity, it is of limited suitability as a quick and easy screening device. We, therefore, validate the 5-item WHO-Five Well-being Index (WHO-5) as a screening tool for PD depression. Two hundred thirteen of 215 recruited PD patients (99.1%) completed the WHO-5. Receiver operating characteristic plots were used to calculate sensitivity/specificity for all cut-off scores for the detection of depression and combined depression/dysthymia as assessed by an independent investigator using the Mini International Neuropsychiatric Interview (MINI). Internal consistency of the WHO-5 was good (Cronbach's alpha = 0.83). WHO-5 showed high validity with adequate detection of depression without differences in the validity indices compared to BDI-1A (P = 0.234). The optimal cut-off value for detection of depression was 12 of 13 points. WHO-5 is a useful, brief, and easy instrument for identifying PD subjects with depression in daily practice.