Anorexia nervosa is notoriously difficult to treat, but little is known regarding the relationship of compliance to treatment outcome. We investigated in 41 adolescents who fulfilled DSM-III-R criteria for anorexia nervosa, the relationship between the completion of a standard psychosocial treatment program, subtypes of anorexia nervosa, and outcome as determined by standardized measurements. These adolescents were observed for an average of 32.4 months. Overall, 29 patients (70%) improved considerably, but 10 (24%) were symptomatic, and 2 (5%) remained in poor condition. There were no deaths. Of the 41 patients, 14 (34%) completed our entire treatment program, 15 (37%) received major treatment and failed in the outpatient follow-up phase only, 7 (17%) dropped out of inpatient treatment before its completion, and 5 (12%) refused treatment in our system altogether. Of all the dropouts, 10 received no further treatment. One patient was admitted to hospital elsewhere but again dropped out in the outpatient phase of that program. Seven patients (17%) received further outpatient treatment only, and 9 (22%) received inpatient and outpatient care and seemingly completed their treatment. Treatment completion significantly affected the measures of global clinical functioning and specific psychopathologic features, but only for those patients who completed the initial program. Bulimic patients did considerably worse on follow-up and were less likely to complete treatment. Patients with restricted anorexia nervosa were more likely to complete treatment than those with a bulimic subtype (P = .03). Differential compliance rates in the two subtypes confound the effects of treatment completion and need to be controlled for in future studies. Depression was not associated with noncompliance but, if present, was associated with poor outcome on follow-up and abated in only a third of those in whom it was initially present.