OBJECTIVE: There are few follow-up studies on outcome for patients with long standing anorexia nervosa (AN) or non-specified eating disorder with several comorbid psychiatric disorders. Inpatient treatment is one option for these patients. The aim of this prospective study was to report one-year follow-up for a consecutive sample of these patients after an inpatient treatment program. METHOD: All 24 patients with a mean age of 28 years and mean duration of an eating disorder of 11 years were treated in a 23-week inpatient group treatment program for AN. Patients were assessed using Eating Disorder Examination interview (EDE), Eating Disorder Inventory (EDI) and Symptom Check List (SCL-90-R) at pre-treatment, post-treatment and at one year after start of treatment. At the follow-up 24 patients were personally interviewed. On admission 12 (50%) had AN, 8 (33%) non-specified eating disorder (EDNOS) and 4 (17%) bulimia nervosa (BN). All had previously suffered from AN and were clinically evaluated to have mostly anorectic psychopathology. RESULTS: Ten (42%) patients had improved at follow-up and 14 (58%) had a poor outcome. There was a moderate but significant improvement on the EDE, EDI and GSI from pre-treatment to follow-up. The improvement occurred during inpatient treatment, and no significant differences from post-treatment to follow-up were found. Patients with low weight on admission showed a significant mean weight increase of about 4 kg at the follow-up. CONCLUSIONS: At one-year follow-up there was a moderate reduction of eating disorder symptoms and general psychiatric symptoms for patients with long standing anorexic symptoms. The improvement occurred during inpatient treatment. Inpatient treatment may be a treatment option in long-time rehabilitation for some of these patients.