During the last few years, deep brain stimulation (DBS) of the subthalamic nucleus (STN) has emerged as a promising therapy, alleviating major motor symptoms of Parkinson's disease (PD). However, in times of growing budgetary limitations, medical decisions are no longer merely based on clinical efficacy, but also on cost-effectiveness. Here we assess treatment costs (i. e. costs for conservative pharmacological treatment and all in-patient admissions) of 46 PD patients for one year before and two years after STN-DBS. The present data show that total treatment costs were increased by 32% for the first year and decreased by 54% for the second year of STN-DBS in comparison with preoperative values while the Unified Parkinson's Disease Rating Scale (UPDRS III) was significantly improved. The increase for the first year after surgery was mainly due to the implantation of the STN electrodes and the stimulation device. Taken together, STNDBS pays off from the second year of stimulation while motor symptoms are significantly improved. The present study provides first data of an important number of patients on clinical effectiveness and expenses in relation to STNDBS.