Respiratory care of patients undergoing open heart surgery should begin in the preoperative period. Patients must stop smoking, and if obese they are encouraged to lose weight. Pulmonary infection is treated and secretions must be eliminated. Postoperative hypoxemia, which is an expected event following anesthesia and surgery, is aggravated by circulatory instability and pulmonary complications. Following open heart surgery pulmonary complications such as atelectasis, congestion, edema, postperfusion lung, pneumothorax, pleural effusion, and hemothorax are common. Respiratory care should be planned to avoid these complications and to treat them promptly should they occur. Routinely every patient is mechanically ventilated for at least 12 to 18 hours following surgery. The type of ventilator used and its parameters are adjusted according to the clinical condition of the patient to maintain adequate oxygenation and to prevent any respiratory acidosis. When indicated, PEEP is applied to improve arterial oxygenation. Respiratory care is extended for at least 5 days after termination of artificial ventilation. Oxygen therapy is given with either a nasal catheter or a mask, according to the patient's need. IPPB and physiotherapy are continued until the patient shows no signs of pulmonary infection and is capable of effectively eliminating secretions. This routine management and extended postoperative respiratory care definitely contribute to the successful outcome of open heart surgery.