The Hepatitis B Research Network (HBRN) is an NIDDK-funded network of 28 Clinical Sites, and Immunology Center and a Data Coordinating Center (DCC). The goals of the network are to study the natural history, pathogenesis, diagnosis and treatments of chronic hepatitis B in children and adults. The HBRN has implemented a longitudinal observational database of children 2-17 years, a longitudinal observational database of adults at least 18 years of age, and three treatment trials for chronic hepatitis B in adults and children.