Sharing of blood glucose monitoring equipment in assisted-living facilities has resulted in at least 16 outbreaks of hepatitis B virus (HBV) infection in the United States since 2004. On October 12, 2010, the North Carolina Division of Public Health (NCDPH) and the Wayne County Health Department were notified by a local hospital of four residents of a single assisted-living facility with suspected acute HBV infection. NCDPH requested HBV testing of all persons who had resided in the facility during January 1--October 13, 2010, and defined an outbreak-associated case as either 1) positive hepatitis B surface antigen and core immunoglobulin M (IgM) results or 2) clinical evidence of acute hepatitis (jaundice or serum aminotransferase levels twice the upper limit of normal) with onset ≥6 weeks after admission to the facility. Records were reviewed for potential health-care--associated exposures and HBV-related risk factors. Infection control practices were assessed through observations and interviews with facility staff.