This study examined the cost effectiveness of treating Anorexia Nervosa, Bulimia Nervosa, and Eating Disorder Not Otherwise Specified (NOS), as well as the effects that modality of therapy (i.e. individual, family, and mixed therapy), license of therapist, and secondary diagnosis had on recidivism and total cost of treatment in the care of these patients. One-thousand and thirty-eight patients (56 males, 982 females) diagnosed with Anorexia Nervosa, 1,674 patients (56 males, 1,618 females) diagnosed with Bulimia Nervosa, and 1,997 patients (197 males, 1,800 females) diagnosed with Eating Disorder NOS were included in this study. Results revealed that family therapy was the least expensive form of therapy in average total cost of therapy. Individuals who had family therapy were 3.3 times less likely to recidivate than those who had individual therapy and 7.5 times less likely to recidivate than those who had mixed therapy. Having a secondary diagnosis on average increased the total cost of treatment by $437.34, irrespective of the type of secondary diagnosis (i.e. depression, anxiety, or substance-abuse). These findings suggest that modality of therapy should be considered in the treatment of Anorexia Nervosa, Bulimia Nervosa, and Eating Disorder NOS. Future research should examine the effects of treatment for individuals with a secondary diagnosis.