Introduction: Chronic pain is the most common syndrome and reason of seeking medical attention, it is an important health problem and presents both medical and nursing diagnosis. It has an important influence on the overall quality of life of the patient and his relatives. Purpose: The purpose of the master's thesis is to identify the factors that influence the quality of the treatment of chronic pain and to learn about the experience of chronic pain from the perspective of the patient, the nurse and the doctor. Methods of work: The research is based on the triangulation of the data obtained by the quantitative and qualitative research method. We prepared the Questionnaire on factors that influence the quality of treatment of chronic pain. The questionnaire was applied on a sample of 101 patients before the start of therapy at the Clinic for pain therapy at the University Medical Centre Ljubljana. All patients also completed the Brief pain inventory before and after the therapy, with which we estimated the effectiveness of the treatment. The response rate of the surveyed patients was 100 %. With the aim of the phenomenological investigation of the experience of chronic pain, we conducted partially structured interviews with groups of six patients, five nurses and seven doctors of anesthesiology. Results: Statistically significant predictors of the effectiveness of chronic pain therapy were the duration of chronic pain, time of waiting for therapy, knowledge about the pain and trust in the prescribed therapy. Results showed that the cooperation of relatives, the patient's expectation of the treatment success, the feeling of helplessness, the patient's previous treatment experience, the patient's trust in the chosen therapy, satisfaction with the prescribed therapy and the understanding of medical treatment are statistically important linked with the quality of treatment of chronic pain. We have shown that the type of therapy itself has an effect on the effectiveness of treating chronic pain. The patient's co-decision about the therapy and satisfaction with clarification and explanation of the prescribed therapy were not proved to be statistically significant effective at treating chronic pain. With the interviews we identified 12 topics that describe the process of treating chronic pain from the point of view of the patient, the nurse and the doctor. Discussion and conclusion: The results show the importance of multidisciplinary treatment of the patient with chronic pain and the recognition of factors that have influence on quality of treatment of chronic pain. Participants in the study gave the least emphasis on the patient's obstruction in various areas of life activity and in the patient's social environment. We find that it is necessary to expand knowledge in the field of monitoring the functioning and obstruction of patients with chronic pain, as well as cooperation with patients' relatives.