The aim of this study was to assess prospectively the long-term outcome in a representative sample of teenage-onset anorexia nervosa (AN) in respect of psychiatric disorders and overall outcome. Fifty-one AN cases, recruited by community screening, with a mean age of onset of 14 years, was contrasted with 51 matched comparison cases at a mean age of 24 years (10 years after AN onset). All 102 cases had been examined at ages 16 and 21 years. At 24 years all probands were interviewed regarding psychiatric disorders (SCID-I) and overall outcome (Morgan-Russell assessment schedule, the GAF). There were no deaths at 10-year follow-up. One in four in the AN group had a persisting eating disorder (ED), including three who still had anorexia nervosa. Lifetime diagnoses of affective disorders and obsessive-compulsive disorder were over-represented in the AN group. Outcome according to Morgan-Russell was poor in 27%, intermediate in 29%, and good in 43%. According to the GAF, half the AN group had a poor psychosocial functioning. These were subjects with either a persisting ED or lifelong problems with social interaction or obsessive-compulsive behaviour. Ten-year outcome of teenage-onset AN is favourable in the majority of cases; most individuals have recovered from their ED and have no other axis I disorder. However, half the AN group reported poor psychosocial outcome, in most cases explained by a persisting ED or chronic obsessive-compulsive behaviour/social interaction problems.