A specific form of family therapy (family-based treatment) is the leading treatment for adolescents with anorexia nervosa. As this treatment has certain limitations, alternative approaches are needed. “Enhanced” cognitive behaviour therapy (CBT-E) is a potential candidate given its utility as a treatment for adults with eating disorder psychopathology. The aim of the present study was to establish, in a representative cohort of patients with marked anorexia nervosa, the immediate and longer term outcome following CBT-E. Forty-nine adolescent patients were recruited from consecutive referrals to a community-based eating disorder clinic. Each was offered 40 sessions of CBT-E over 40 weeks from a single therapist. Two-thirds completed the full treatment with no additional input. In these patients there was a substantial increase in weight together with a marked decrease in eating disorder psychopathology. Over the 60-week post-treatment follow-up period there was little change despite minimal subsequent treatment. These findings suggest that CBT-E may prove to be a cost-effective alternative to family-based treatment.