Considerable progress has been made in the past decade in developing vaccines against the most important bacterial and viral infections of the gastrointestinal tract. Members of the Division of Geographic Medicine in the Center for Vaccine Development have played a prominent role in the laboratory development and clinical testing of these vaccines. A new oral typhoid vaccine, Ty21a, has been licensed in the United States. A genetically engineered live oral cholera vaccine developed in the CVD is undergoing clinical trials in cholera-endemic areas. Multiple vaccine candidates against Shigella, enterotoxigenic E. coli, and rotavirus are in clinical trial in the United States or overseas. Rapid advances in molecular biology, together with new knowledge of mucosal and cellular immunity, will produce more vaccine candidates in the future. The CVD intends to be in the forefront of these developments.