Pulmonary air embolism is a potentially lethal complication of catheter ablation of cardiac arrythmias.We present a 50 year old man with pulmonary embolism during cryoballoon ablation of atrial fibrillation. Deep breath of patient while inserting the sheath into left atrium from right femoral vein was main cause of pulmoary air embolism. Air bubble was dispersed by hitting on it with the pigtail catheter and pulmonary flow was achieved. The patient was discharged without any sequelae.