Body weight changes occur during the clinical course of Parkinson's disease (PD) and with surgical treatment, but the effect of dopaminergic treatment on weight is unknown. Body mass index (BMI), Hamilton depression scale score (HDS), and Unified Parkinson's Disease Rating Scale III (UPRS-III) were measured before and 3 months after starting pramipexole in 28 PD patients. Pramipexole produced a significant weight increase, as well as motor and mood improvement (P <0.001). HDS and BMI changes were mildly related (P = 0.05). A direct effect of pramipexole on limbic D(3) receptors involved in the control of feeding may be responsible for weight gain in PD.