Anorexia Nervosa (AN) and Major Depressive Disorder (MDD) are frequent comorbid conditions. It is unclear how MDD affects intensive emergency treatment and outcome. Eighty-seven AN inpatients were analyzed, twenty-two suffered also from MDD. Individuals with AN and MDD at admission had no remarkable differences in psychopathology, but a full diagnosis of MDD - and not just the presence of depressive symptoms - was associated with longer length of stay and worse clinical outcome (weight restoration, increase of caloric intake). Health care policies might consider that MDD comorbidity, regardless of AN clinical severity, affects the efficacy and timing of acute treatments.