[en] Hypocortisolism is an uncommon condition. Its association with myopathy and respiratoryfailure has only rarely been described. We report the case of a 52 year-old woman presenting with progressive dyspnoea. Work-up revealed a severe restrictive syndrome with hypoxaemia. Further investigations showed hypocortisolism of pituitary origin. Response to hydrocortisone allowed us to conclude to an unusual case of hypocortisolic myopathy affecting the respiratory muscles.