Previous studies have shown that pramipexole might have the potential to improve depressive symptoms in patients with Parkinson's disease. To provide more evidence, in five Japanese patients at Hoehn & Yahr stage 1-3 we evaluated the Unified Parkinson's Disease Rating Scale (UPDRS), Hamilton Depression Rating Scale (HAMD) and Montgomery Asberg Depression Rating Scale (MADRS) at our hospital. After the pramipexole treatment, each total score of UPDRS, HAMD and MADRS significantly decreased compared with that before the treatment. Our data indicate that pramipexole improves depressive symptoms in patients with Parkinson's disease.