Objective This study investigated the effectiveness of sequenced cognitive–behavioural therapy followed by interpersonal psychotherapy for patients with eating disorder not otherwise specified (EDNOS) type three by comparing individual (IND) and group therapy (GRP). Method Thirty-five EDNOS participants were matched and randomized to 23 sessions of IND or GRP. Intention-to-treat analysis was used and participants were measured pre-, post-treatment and at 1- and 2.5-year follow-up. Results Both treatment modalities were efficacious from pre- to post-treatment and to the 1- and 2.5-year follow-up. There was one significant difference between GRP and IND at the 2.5-year follow-up for SCL-90 (global severity index) (F = 5.01; p < 0.03) favouring GRP. Discussion The treatment appears to result in increased recovery and remission from post-treatment to follow-up in favour of GRP. More research is required before a specific treatment approach for EDNOS type three can be recommended. Copyright © 2005 John Wiley & Sons, Ltd and Eating Disorders Association.