A 3-month-boy weighing 1,968 gm with absent pulmonary valve associated with tetralogy of Fallot, who suffered from severe respiratory distress, underwent emergency operation. Preoperatively, the patient had atelectasis of left lung, since left main bronchus was compressed by aneurysmal dilatation of the main pulmonary artery. Aneurysmorraphy and suspension of the pulmonary artery with retrosternal fascia was performed successfully. This procedure is a simple and useful method of relief from airway obstruction at the first stage for such critically ill infants.