Computer-based quality assurance of specialist eating disorder (ED) care is a possible way of meeting demands for evaluating the real-life effectiveness of treatment, in a large-scale, cost-effective and highly structured way. The Internet-based Stepwise system combines clinical utility for patients and practitioners, and provides research-quality naturalistic data. Stepwise was designed to capture relevant variables concerning EDs and general psychiatric status, and the database can be used for both clinical and research purposes. The system comprises semi-structured diagnostic interviews, clinical ratings and self-ratings, automated follow-up schedules, as well as administrative functions to facilitate registration compliance. As of June 2009, the system is in use at 20 treatment units and comprises 2776 patients. Diagnostic distribution (including subcategories of eating disorder not otherwise specified) and clinical characteristics are presented, as well as data on registration compliance. Obstacles and keys to successful implementation of the Stepwise system are discussed, including possible gains and on-going challenges inherent in large-scale, Internet-based quality assurance.