Eating disorders (ED), including anorexia and bulimia nervosa, are chronic illnesses with periods of symptom exacerbation and remission. Because symptoms are usually present from 6 to 24 months before a diagnosis is made, aetiological agents are believed to be active well before symptoms appear. It is proposed that neuropsychological deficits in various cognitive domains preexist and underlie the aetiology of ED. This paper provides a comprehensive review of the literature relevant to neuropsychological deficits in ED patients and explores the relationship between cognitive deficits, psychosocial development, and the development of ED. Although the role of neuropsychological deficits in the evolution of ED requires further research, the proposed association has significant implications for clinical practice.