A 65-year-old man developed respiratory distress during insertion of a central venous catheter (CVC). The presence of gas in the pulmonary trunk and ascending aorta was observed on computed tomography (CT) scans performed immediately after insertion, and paradoxical air embolism (PAE) was diagnosed. There were no symptoms of cerebral or coronary arterial embolism, and the patient was maintained in the same supine position as during CVC insertion. CT conducted after 200 min confirmed disappearance of the gas, and the resting position was discontinued. No subsequent symptoms of PAE occurred. In this patient with respiratory distress during CVC insertion, CT revealed PAE, and PAE was resolved and systemic arterial embolism did not occur by maintenance of the supine position and O(2) administration. This case also highlights the potential risk for the occurrence of asymptomatic PAE related to CVC insertion.