Personality is a complete psychological structure that touches on emotional and cognitive traits, a person's temperament, character, attitudes, interests, moral personalities and forms of experiencing and reacting. That is, in the psychological sense, personality is the totality of a certain person. Each person has his own way of experiencing, reacting and his own personality traits, and each individual is recognizable by them. According to statistics, almost 15% of the world's population is affected by this disorder. First, we will deal with the concept of personality, without which we would not be able to fully understand personality disorder. This final paper will touch upon personality development and describe personality theories and models. The developmental stages of personality will be mentioned and the symptoms that occur in patients with borderline personality disorder will be touched upon, as well as diagnostic methods for the aforementioned disorder. Furthermore, treatment methods will be described and the types of therapy will be explained separately. The most important item of this final thesis is the health care of patients with a personality disorder, it will refer to nursing diagnoses that are specific for patients with a psychiatric diagnosis. Continuous nursing care for patients with borderline personality disorder requires specific knowledge and skills of the nurse. The nurse is obliged to set goals and develop a complete health care plan. Also, as a member of a multi-disciplinary team, the nurse has a major role in recognizing, detecting and even treating the patient's health care problems. This is one of the reasons why each patient should be approached uniquely, holistically and therapeutically. We must certainly not leave out very important education in order to help patients in the most adequate way possible.