The problem of chronic critical illness therapy is relevant all over the world. Revealing the metabolic function in patients in chronic critical condition is an important link in the development of adequate treatment and rehabilitation tactics. The aim - identification of metabolic features in chronic critical patients after brain injury in the first 3 days from the moment of admission to the rehabilitation center. Material and methods. Single-center observational study included a group of 25 patients with chronic critical illness, aged 38.7±14.0 years with body mass index 20.8± 4.3 kg/m2 (min 14.5; max 29.7), who were on independent breathing through a tracheostomy tube, and who have pronounced neurological disorders in the form of depression of minimally conscious state, FOUR scale from 12 to 16 points, as well as bedsores 1-2 stage and polysegmental pneumonia. The patients underwent indirect calorimetry and analysis of biochemical parameters of protein, carbohydrate, fat and mineral metabolism, as well as the level of nitrogen excretion with urine. Results and discussion. The data obtained indicate that chronic critical ill patients with the consequences of traumatic brain injury had pronounced metabolic disorders, mainly of a protein component. Total protein level decreased up to 61.0±9.4 g/l (min 39.1; max 83.1), albumin up to 30.2±6.0 g/l (min 17.4; max 37.8), prealbumin up to 0.13± 0.06 g/l (min 0.04; max 0.23) and transferrin up to 147.7±37.7 mg/dl (min 84.0; max 209.0). The patients' requirement in protein was 106.4±38.5 g/day (min 57.1; max 160.5) or 1.55±0.46 g/kg/day (min 0.75; max 2.22). The level of resting energy expenditure measured by indirect calorimetry was 1549.1±421.8 kcal/day (min 673.0; max 2430.0) or in terms of body weight 24.8±7.6 kcal/kg/day (min 12.4; max 45.8). Conclusion. The data obtained indicate a continuing catabolic phase in patients more than 30 days after the primary injury, which led to their chronic critical condition. Copyright© GEOTAR-Media Publishing Group.