Objective: This randomized control trial is an evaluation of the effectiveness of enhanced cognitive behavioral treatment (CBT-E) for eating disorders adapted for a group setting. The study aimed to examine the effects of group CBT-E on eating disorder psychopathology and additional maintaining pathology. Method: A transdiagnostic sample of individuals with eating disorders with a BMI ≥ 18 kg/m2 (N = 40) were randomized to an immediate-start or delayed-start condition so as to compare therapeutic effects of group CBT-E with a waitlist control. Global Eating Disorder Examination Questionnaire (EDE-Q) scores, BMI, and measures of Clinical Perfectionism, Self-Esteem, Interpersonal Difficulties, and Mood Intolerance were measured across the 8-week control period, throughout the group treatment and at 3-months post-treatment. Results: Over 70% of those who entered the trial completed treatment. The first eight weeks of group CBT-E were more effective at reducing Global EDE-Q scores than no treatment (waitlist control). By post-treatment, good outcome (a Global EDE-Q within 1 SD of Australian community norms plus BMI ≥ 18.5) was achieved by 67.9% of treatment completers and 66.7% of the total sample. Symptom abstinence within the previous month was reported by 14.3% of treatment completers and 10.3% of the total sample. Significant reductions in Clinical Perfectionism, Self-Esteem, Interpersonal Difficulties, and Mood Intolerance were also observed. Discussion: This study demonstrated that a group version of CBT-E can be effective at reducing eating disorder psychopathology in a transdiagnostic sample of individuals with eating disorders. Group CBT-E could provide a means of increasing availability of evidence-based treatment for eating disorders. [ABSTRACT FROM AUTHOR]