We report a case of interruption in the supply of breathing gas during general anesthesia caused by malposition of the Drager Vapor 2000® vaporizer, which was accidentally tilted and lifted off the Selectatec manifold of the anesthesia machine. Because the patient was an 1-month-old infant, we couldn't check if he had experienced awareness with recall. We emphasize the importance of checking the anesthetic vaporizer after mounting it on the back bar of the anesthesia machine.