BACKGROUND AND OBJECTIVES To describe the development and investigate the psychometric properties of a new instrument to measure health-related quality of life (HRQoL) for individuals with an eating disorder (ED). METHODS Seven focus groups were convened and an extensive literature review was carried out to generate the items. The first draft of the questionnaire was pilot tested. Three hundred twenty-four ED patients took part in the final field study. The 12-Item Short Form Health Survey, the Eating Attitudes Test-26, and two items from the Eating Disorders Inventory-2 also were applied to examine the concurrent validity. Factor analysis, item scale correlation correcting for overlap, test-retest, Cronbach's alpha coefficient, known-groups validation, and the sensitivity of the questionnaire in different populations also were examined. RESULTS The final Health-Related Quality of Life in Eating Disorders (HeRQoLED) questionnaire consisted of 50 items. Principal axis factor analysis identified eight subscales. Concurrent validity showed correlations >.40 with the criteria measures. Excellent reliability and stability were obtained. The HeRQoLED was sensitive in discriminating both between known-different groups and from the general population. CONCLUSION The results provide evidence of the good psychometric properties of the new HeRQoLED questionnaire, except for one domain, which had to be eliminated.