The Alaska Native population includes persons of Eskimo, Indian, and Aleut descent. In 1998, an estimated 104 305 Alaska Natives were living in Alaska. Nearly all Alaska Natives receive their health care through a three-tiered integrated health care system, with primary care given in villages, secondary care in regional hospitals, and tertiary care at the Alaska Native Medical Center in Anchorage. The Hepatitis B Carrier Registry contains records of all Alaska Natives who have had at least one positive test result for HBsAg. All persons who were HBsAg positive on consecutive specimens obtained at least 12 months apart, determined either retrospectively or prospectively, were defined as hepatitis B carriers and were included in the analysis. When newly HBsAg-positive persons were identified, the serum bank located at the Arctic Investigations Program of the Centers for Disease Control and Prevention in Anchorage, which contains several hundred thousand serum specimens stored since the early 1970s, was searched, and if serum specimens from these persons were found, they were tested for HBV seromarkers to attempt to establish time of infection and duration of carriage.