In recent years, with the advent of the so-called 'third wave' cognitive-behavioral therapy - relationship importance was strengthened. The importance of the therapeutic relationship in working with patients with personality disorders is uderlined. They bring into the therapy their beliefs about themselves, others and the world, the patterns of emotional and behavioral response associated with them, which usually are not adaptive and provoke to seek expert help. The therapeutic relationship allows the therapist conceptualize the problem of the patient and to fine-tune the techniques selection, and becomes a space to disclosure and checking his belief and interpretation for the patient. In the case of patients with personality disorders the therapeutic relationship is both a treatment and the means to achieve the target of therapy. The therapeutic relationship is a necessary but insufficient condition for changes in therapy. It works in combination with techniques which allow for effective assistance to the patient. Relationship and the techniques of cognitive-behavioral therapy are not separated areas, but rather the integrating aspects of therapeutic process. The article shows the current understanding of the relationship in cognitive-behavioral therapy and presents selected problems arising in this respect in the treatment of patients with personality disorders.