Diaphragm dysfunction and weaning-induced pulmonary oedema are two important causes of weaning failure. Diaphragm dysfunction can reduce contraction force of the diaphragm, compromising pulmonary ventilation loss and causing a subsequent weaning failure. Large negative swings in intrathoracic pressure during weaning tend to increase the venous return and the left ventricular afterload, contributing to weaning-induced pulmonary oedema and respiratory distress. This article reviews the mechanisms, diagnosis and strategies of treatment of diaphragm dysfunction and weaning-induced pulmonary oedema.