The aim of the study was to estimate health state utility values in newly diagnosed idiopathic Parkinson's disease (PD) for use in the assessment of health-related quality-of-life (HRQL), and in the estimation of quality-adjusted life-years (QALYs). Data from 162 patients enrolled in a community-based incidence study of PD were used to estimate health state utility values. Self-report data from the EQ-5D, a generic measure of HRQL, were used to derive preference-based health state utility values. The impact of motor and non motor symptoms, and other clinical and demographic factors, on the derived EQ-5D health state values was examined in univariate and multivariate analyses. The mean health state utility value for recently diagnosed PD patients was estimated at 0.65 ± 0.27. Significant reductions in health state values were attributable to pain (-0.18), motor functioning (-0.16), depression (-0.12), and insomnia (-0.11). Depression had its greatest impact (-0.19) in patients in the less severe stages of PD (i.e. Hoehn Yahr stages ≤2.5). This study shows, through the presentation of QALY values, that there is scope to achieve significant health gains in newly diagnosed idiopathic PD patients via improved management of pain, depression and insomnia, alongside the treatment of primary motor symptoms.