Objectives: Earlier versions of the Structured Interview for Anorexic and Bulimic Disorders (SIAB) were modified in order to include new research findings and to update the expert rating interview to the diagnostic criteria of DSM-IV and ICD-10. The semistandardized interview was developed for reliable and valid assessment of the specific as well as the general psychopathology of eating disorders. Method: Data from SIAB-EX interviews (current and past/lifetime symptom expression) were available from three samples: (a) 330 eating-disordered patients assessed at the start of treatment, (b) 148 former eating-disordered patients with anorexia nervosa (AN) or bulimia nervosa (BN) assessed at follow-up, and (c) 111 community controls. Sixty-one of the 87 items of the SIAB-EX with a 5-point scale were factor analyzed. Results: Principal components analyses with varimax rotation produced the following six components of the SIAB-EX (lifetime): (I) Body Image and Slimness Ideal; (II) General Psychopathology; (III) Sexuality and Social Integration; (IV) Bulimic Symptoms; (V) Measures to Counteract Weight Gain, Fasting, and Substance Abuse; and (VI) Atypical Binges. The factor solution for the current symptom expression was very similar to that based on lifetime symptom expression. Average item and factor scores are given for six groups of eating-disordered patients and controls. High interrater reliability was established for both current and the past symptom expression. Cronbach's alpha coefficients indicated good internal consistency for five of the six components of the SIAB-EX. DSM-IV and ICD-10 diagnoses for eating disorders can be derived directly or by using a computer algorithm from the SIAB-EX. A detailed 90-page manual facilitates the training of interviewers. Conclusion: The 87-item SIAB-EX was originally developed for detailed assessment of eating disorders cross-sectionally and longitudinally. The updated version which allows for diagnosis according to DSM-IV and ICD-10 is described here. © 1998 by John Wiley & Sons, Inc. Int J Eat Disord 24: 227–249, 1998.