Background: The effectiveness of enhanced cognitive behavioural Therapy (CBT-E) for adults with a range of eating disorder presentations within routine clinical settings has been examined in only two known published studies, neither of which included a follow-up assessment period. Aim: The current study aimed to evaluate the effectiveness of CBT-E within an out-patient eating disorder service in Brisbane, Queensland, Australia, and incorporated a follow-up assessment period of approximately 20 weeks post-treatment. Method: The study involved 114 adult females with a diagnosed eating disorder, who attended an average of 20–40 individual CBT-E sessions with a psychologist or a psychiatry registrar between 2009 and 2013. Results: Of those who began treatment, 50% did not complete treatment, and the presence of psychosocial and environmental problems predicted drop-out. Amongst treatment completers, statistically and clinically significant improvements in eating disorder and general psychopathology were observed at post-treatment, which were generally maintained at the 20-week follow-up. Statistically significant improvements in eating disorder and general psychopathology were observed amongst the total sample. Conclusions: The findings, which were comparable to the previous Australian effectiveness study of CBT-E, indicate that CBT-E is an effective treatment for adults with all eating disorders within out-patient settings. Given the high attrition rate, however, minimizing drop-out appears to be an important consideration when implementing CBT-E within clinical settings.