This study is a preliminary investigation of the reliability and validity of the Behavior Rating Inventory of Executive Function - Adult Version (BRIEF-A) in a clinical sample of patients with eating disorders (ED). Participants were 252 adult females who were referred to a centre for the treatment of EDs, as well as 31 individuals who completed the informant version of the BRIEF-A. Patients completed the BRIEF-A and other psychological measures on one occasion during their initial clinic visit, and informants nominated by patients completed the informant version at home. Reliability analyses revealed high internal consistency (Cronbach's alpha) of the two indices (Metacognition Index and Behavioral Regulation Index), and for the Global Executive Composite (GEC) of the BRIEF-A (α = .96). Convergent validity was shown by a high positive relationship between the self-report and informant-report versions of the BRIEF-A, and between the GEC and the Anxiety and Depression scales. Construct validity was assessed by an exploratory and confirmatory factor analysis. The BRIEF-A may be a reliable and valid tool for measuring executive functioning (EF) in an ED population, and may serve as an initial screening tool of EF for clinicians and researchers.