Eating disorders are defined by a complex interaction between emotional, cognitive and interpersonal challenges in addition to behaviours used to control weight or shape. One of the major challenges with the treatment of eating disorders is ambivalence, low motivation to engage in treatment, and a high treatment dropout rate. Motivational Interviewing is a therapeutic style that elicits intrinsic motivation from within the patient to drive behaviour change. The current study provides an evaluation of the effectiveness of the two pretreatment group motivation interventions delivered by the South Island Eating Disorder Service. Significant changes in motivational stage of change were observed in both the Motivation and Education Group and the pure Motivation Group. Significant improvements in patient readiness, confidence and importance to change as well as treatment attendance were identified in the pure Motivation Group. Recommendations for future treatment development are presented.