In this paper, we define mandatory treatment components as 'treatment non-negotiables' and suggest that the manner in which non-negotiables are set and implemented has a significant impact on therapeutic alliance and outcome in the eating disorders. Common non-negotiable difficulties are reviewed and a philosophy is provided that can be applied to all stages of treatment: non-negotiables need to have a sound rationale, be consistently implemented, not take the client by surprise, and maximize client autonomy. We do not believe that a given non-negotiable is 'right' or 'wrong', but rather that treatment non-negotiables are optimally developed in response to the client population, treatment setting, clinician values and beliefs about change, and client and clinician input and experience. Copyright (c) 2006 John Wiley & Sons, Ltd and Eating Disorders Association.