Using the clinicopsychopathological method and experimental psychological techniques the mechanisms of psychological defence were studied in 46 patients with chronic renal failure. The adaptation character of the mechanisms of psychological defence was shown in terms of the dynamics of their types depending on the stage and treatment of the disease. The role of the sex, premorbid personality type of the patient, the type of the disease course, nature of mental traumas in the formation of psychological defence is validated. The relationship between the development of mental disorders and the mechanisms of psychological defence is analyzed.