This paper describes a new cognitive model of bulimia nervosa. It provides a detailed account of the development of the disorder and explains, in detail and encompassing cognition, behaviour, emotion, and physiology, how binge eating is maintained. Relevant maintaining factors include positive beliefs about eating, negative beliefs about weight and shape, permissive thoughts, and thoughts of no control. Relevant developmental factors include negative early experiences, negative self-beliefs, schema compensation processes, and different types of underlying assumption. Recent empirical findings on which the new model is based, and which support the model, are described. Existing observations and findings are also presented, and their consistency with the new model is confirmed. Novel features of the model are highlighted, and phenomena unexplained by existing cognitive models of bulimia nervosa, including treatment failure and relatively poor outcome following treatment with cognitive therapy, are assessed in the light of the new model. The relationship to recent findings on the role of dieting in bulimia nervosa and to developments in the understanding or normal eating is considered. Implications for basic and treatment-related research are then discussed. Finally, the clinical implications of the new model, including the use of schema-focused techniques, are briefly discussed.