The purpose of the present case report is to present a case of bilateral diaphragmatic paralysis as a complication of open-heart surgery. A 47-year-old male was operated for aortic and mitral valve replacement. After discontinuation of sedation, bilateral diaphragmatic paralysis as well as motor and sensitive dysfunction in the four extremities was observed. The patient remained with mechanical ventilation support for twenty months. Two years after the operation a complete normalisation of the diaphragmatic motion was observed. Although uncommon, bilateral diaphragmatic paralysis after open-heart surgery could take place, being necessary long term mechanical ventilation support until recovery.