BACKGROUND/AIMS: The importance of nutrition is clearly established in the management of the critically ill patient: malnutrition contributes to immune incompetence, poor wound healing, increased postoperative complication and prolonged hospital stay. The interaction between nutritional status, nutritional supply and respiratory function is important in the management of the Chronic Obstructive pulmonary Disease (COPD) patients under mechanical ventilation (MV). In the present study was analyzed the benefits of combined nutritional support in patients with COPD under MV.METHODOLOGY: One hundred ninety two (192) patients with COPD were admitted to our Intensive Care Unit (ICU), due to severe respiratory failure of whom 163 (84.9%) patients were under MV. In 18 (11.04%) patients after the 10th day under MV and due to severe malnutrition (serum albumin < 2.5 gm/dl, total lymphocyte count (TLC) < 900/mm3), added in the enteral nutrition (EN) of 1800 Kcals and parenteral nutrition (PN) of 2000 Kcals, at high concentration in lipids from central venous catheter.RESULTS: Seven (38.89%) patients on the 4th day, after combined nutrition, had a positive balance of nitrogen and normal level of the nutritional indices, 4 (22.22%) were on normal level on the 5th day, 3 (16.67%) on the 6th day, 1 (5.56%) on the 7th day after combined nutrition. We had no complications from the combination of EN and PN. Conclusively, of these 18 patients that were given both EN and PN, 15 (83.33%) were weaned from MV and continued the combined nutritional support for 3 days, while 3 (16.67%) died during the combination of EN and PN, without having achieved a normal level of the indices of nutrition and without a positive balance of nitrogen.CONCLUSIONS: In this study was found that: 1. patients with COPD under MV rapidly developed malnutrition, 2. the combination EN and PN without complications contribute to the weaning from MV, 3. positive nitrogen balance and normal increases of nutrition are achieved after the 4th day of combined nutrition and 4. Early addition of EN and PN in patients with COPD under MV, probably accelerates the weaning from MV, reduces hospitalization, changes the outcome and reduces the cost of hospitalization of patients with COPD under MV in ICU.