Esophageal variceal bleeding owing to portal hypertension is a potential threat in pediatric patients awaiting liver transplantation. We report a case of a three-year-old boy with severe congenital hepatic fibrosis, Caroli's disease, and portal hypertension who developed a life-threatening variceal hemorrhage for the first time in his life during commercial air transport to a liver transplantation center. Factors precipitating variceal bleeding are discussed, particularly those resulting from changes in altitude. It is recommended that prophylactic treatment for variceal bleeding be at least considered in children awaiting liver transplantation prior to prolonged air transportation. Because of differences in capabilities of treatment providers in various locales, and because there are as yet no conclusive data, the treatment of choice must be decided on an individual basis. Equipment for treating in-flight hemorrhage should be available.