Electroconvulsive therapy (ECT) is rarely, if ever, considered for the treatment of severe anorexia nervosa (AN) or other eating disorders comorbid with an affective illness. Mood disorders are common in these patients, and psychotropic medications, although frequently used, have limited evidence of benefit in AN or copresenting depressive symptoms. Even when the illness is life threatening, ECT as a treatment may be overlooked. We present a case of an adolescent girl with severe AN and comorbid major depressive disorder with suicidality. This patient failed multiple medication trials but went on to experience complete remission from both the symptoms of her AN and major depressive disorder after undergoing a course of bilateral ECT. Electroconvulsive therapy may prove to be a fast and effective treatment strategy for mood disorders and suicidality in the setting of comorbid AN in adolescents.