ABC-DEF framework is at the core of rational emotive behavior therapy. It is a highly flexible framework and has proven to be applicable to many emotional disorders. We cannot take for granted, however, that this framework can be used successfully with all clients, particularly with those suffering from severe disorders or personality disorders. In fact, the difficulties of these clients in recognizing, naming and reflecting upon states of mind, their dysregulated emotions and self-defeating behavior, and their difficulty in establishing a strong working alliance with a therapist may hamper the correct implementation of the ABC-DEF framework and the disputing of their irrational beliefs. This paper aims to describe in detail the challenges that clients with personality disorders may pose during treatment and offer possible technical suggestions, derived from either REBT or non-REBT literature, that can help REBT and CBT practitioners adapting their interventions to resistant clients