This is a case report of a 21-year-old male patient with Cornelia de Lange syndrome (CdL) and unrepaired tetralogy of Fallot scheduled for dental treatment under general anesthesia. Anticipated dental care consisted of restorative treatment and extractions. Surgical correction of the patient's congenital cardiac abnormalities had not occurred by the time of dental treatment. As such, the developed anesthetic plan included the following goals: prevention of any anoxic episodes or spell and preparation for difficult airway management due to micrognathia secondary to CdL. To help ensure adequacy of oxygenation during induction, the normal anesthetic face mask was specially modified with a hole to permit use of the fiberoptic scope during induction and intubation. With preoperative consultation involving a cardiologist as well as the use of the modified mask, general anesthesia was safely administered without any complications.