Deep brain stimulation (DBS) is an effective but costly treatment for advanced Parkinson's disease (PD). This study examined the cost-effectiveness of DBS in relation to its improved effectiveness, in order to help funding decision makers decide whether the treatment should be adopted. The incremental cost-effective ratio (ICER) per quality-adjusted life year (QALY) has been benchmarked as being between US$50,000 and US$100,000 by the United States agencies, whereas it is under €30,000 per QALY in Europe.