Aim: The aim of the current study was to collect clinical normative data for the Clinical Impairment Assessment questionnaire (CIA) and the Eating Disorder Examination Questionnaire (EDE-Q) from adult patients with eating disorders (EDs). This study also examined unique contributions of eating disorder (ED) symptoms on levels of ED-related impairment.Methods: A sample of 667 patients, 620 females and 47 males, was recruited from six specialist centres across Norway. The majority of the sample (40.3%) was diagnosed with eating disorder not otherwise specified (EDNOS), 34.5% had bulimia nervosa (BN), and 25.2% were diagnosed with anorexia nervosa (AN).Results: There were significant differences for global EDE-Q and CIA scores between females and males. In the female sample, significant differences were found on several EDE-Q sub-scales between the AN and BN group, and between the AN and EDNOS group. No significant differences were found between the diagnostic groups on the CIA. In the male sample, no significant differences were found between diagnostic groups on the EDE-Q or CIA. A multiple regression analysis revealed that 46.8% of the variance in impairment as measured by the CIA was accounted for by ED symptoms.Conclusions: Body mass index, Eating Concern, Shape/Weight Concern, and binge eating served as significant, unique predictors of impairment. The results from the present study contribute to the interpretation of EDE-Q and CIA scores in ED samples.