According to popular opinions therapeutic relationship doesn't play a significant role in cognitive-behavioral therapy. Furthermore it is frequently assumed that cognitive therapist doesn't pay attention to processes taking place during the session, focuses solely on a realization of an earlier planned protocol and convinces patient to rational thinking minimizing the role of emotions. Contrary to this beliefs CBT therapists often focus on a therapeutic relationship and use it in a process of treatment. This applies especially to personality disorders. The aim of this paper is to present a therapy falling into the third wave of CBT – dialectical behavior therapy of Marsha Linehan (dialectical behavior therapy – DBT) – emphasizing unappreciated and curing aspects of a relationship between patient and therapist. DBT therapist discusses with a patient important matters in their relationship, is responsive and flexible during the session and concentrates on a work with emotions of a patient. In this paper are discussed: the theoretic model of a borderline personality disorder according to DBT, basic assumptions of therapy, contingency management, methods of limits setting, possible difficulties of a therapist and ways of dealing with them.