An iatrogenic venous air embolism caused by computed tomography (CT) injector occurred in a 74-year-old man undergoing abdominal-pelvic CT for evaluation of an abdominal aortic aneurysm (AAA). During the initial inspection scan of the thoracic part, a large amount of air was detected in the right ventricle, but no contrast medium was noted in the aorta. Surface oxygen was given immediately, and the patient was placed in the left lateral decubitus position on the CT bed. During that time he had no symptoms except coughing. CT revealed no air in the brain or pulmonary vein, and he was returned to his room 55 minutes after the incident. There were no complications during a six-month follow-up period. The importance of daily risk management and immediate proper after care to prevent such accidents was reconfirmed.