This study examined the reliability, validity and internal structure of the newly developed, interview-based Schedule for the Assessment of Insight in Eating Disorders (SAI-ED) and the relationships of insight with demographic and clinical characteristics in EDs. Ninety-four female patients - 44 with anorexia nervosa (AN) and 50 with bulimia nervosa (BN) - were assessed with SAI-ED. The Brown Assessment of Beliefs Scale was used to evaluate convergent validity of SAI-ED. Hierarchical cluster analysis and multidimensional scaling were used to identify insight components and assess their inter-relationships. The final 8-item SAI-ED demonstrated good psychometric properties. Inter-rater and test-retest reliabilities were high. Three subscales of SAI-ED were identified which measure major insight components: awareness of illness, awareness of symptoms, and treatment engagement. Patients with AN had significant lower score on SAI-ED than patients with BN. Impaired insight was associated with: (a) lower current and lowest lifetime BMI and more severe dietary restrain in AN, (b) illness duration, severity of overall ED symptoms, body-related concerns and obsessionality in BN. Insight is a multidimensional construct in EDs associated with different clinical aspects in AN and BN. The SAI-ED is a valid and reliable tool for the assessment of insight in EDs patients.