In this report we describe a patient with recurrent episodes of acute pulmonary oedema after aortic and mitral valve surgery. The first episode of pulmonary oedema was caused by mitral valve dysfunction. The second episode of pulmonary oedema was not clearly associated with a mitral valve problem, but reoperation was performed in the absence of another explanation. After the third episode of acute pulmonary oedema occurred, the diagnosis of obstructive sleep apnoea syndrome (OSAS) was considered and confirmed. After starting treatment with continuous positive airway pressure (CPAP) during his sleep the patient had no further episodes of acute respiratory failure. Our case demonstrates that acute pulmonary oedema after cardiothoracic surgery can be caused or at least be precipitated by OSAS and should be suspected in patients with unexplained episodes of (recurrent) pulmonary oedema. (Neth Heart J 2008;16:310-2.).