Malnutrition is often observed in patients with chronic respiratory failure, particularly during acute episodes. In this short review, we discuss the nutritional status of patients suffering from chronic obstructive pulmonary disease (COPD) in the stable and acute phases, and the consequences of malnutrition for some components of the respiratory system (respiratory muscles, pulmonary tissue and ventilation control). Finally we propose a realimentation protocol, although at present time there is no proof that renutrition influences short or long term prognosis in such patients.