We analyzed the influence of co-occurring obsessive-compulsive disorder (OCD) on response to eating disorder (ED) treatment among 2,971 female inpatients. We assessed treatment response using Eating Disorder Inventory-2 and DSM-IV ED criteria. Multivariate analyses included sociodemographics, illness severity, and co-occurring Axis I/II diagnoses. ED inpatients with OCD had greater ED severity than those without OCD. However, no differences occurred in short- and intermediate-term ED outcomes. Patients with and without OCD evidenced the same degree of change in EDI-2 scores admission-to-discharge and discharge-to-one-year; and 93% of patients both with and without OCD no longer evidenced a DSM-IV ED diagnosis one-year post-discharge. Results suggest that with co-occurring OCD treated using evidence-based interventions ED inpatients with and without OCD may have similar prognoses.