Remission rates after treatment for bulimia nervosa can be considered insufficient. The study aimed to explore the perspective of expert psychotherapists on possible reasons for non-response and recommendations for an optimized treatment. Experts filled in a questionnaire that comprised questions about possible reasons for low remission rates as well as ratings of interventions suggested for different treatment phases and subgroups of patients. 56 experienced therapists could be included in the survey. Ambivalence of patients, insufficient training of therapists and heterogeneity of the patient group were most often rated as possible reasons for insufficient outcomes. For optimized treatment, therapists recommended a combination of cognitive-behavioral and psychodynamic techniques, depending on treatment phase and patient characteristics. Further research should examine, if a more specific training of therapists, a more integrative approach and flexible adaptations of interventions to patients' characteristics are effective strategies to improve outcome.