Morbid obesity is a condition of excessively high accumulation of body fat, exceeding normal levels, which can be life‑threatening. A patient is diagnosed as morbidly, or severely, obese when their BMI exceeds 40 kg/m2. Lasting a long time, not only does it impair the normal functioning of their organism, but can also influence the progression of multiple comorbidities. Severe obesity affects life quality in patients on health, psychological, and social levels. Nowadays, the obesity treatment program considered to be the most effective is bariatric surgery. As causes as well as effects of morbid obesity concern numerous aspects of patient’s functioning, it is essential to include specialists of diverse fields in patient’s care, creating multidisciplinary teams. Psychologists play an indispensable role in the treatment process: using tailored tools and techniques, they conduct psychophysical assessments, diagnose causes of the disorder, motivate, and support the patient at each stage of the treatment. Obesity treatment is not a terminable process; it is a continuum. The process is marked by a certain risk of weight gain recurrence. Only the holistic approach to obesity therapy results in its effectiveness.