Prevalence of hepatitis B virus (HBV) markers, including occult HBV, has not been described in diverse cohorts among HIV-infected patients. The objective of this study was to assess prevalence and significance of active and occult HBV infection in an HIV-positive US cohort. A random sample was taken from 2 prospective multicenter treatment intervention cohorts. The sample population (n = 240) was HIV-1 infected and highly active antiretroviral therapy–naive. Prevalence of HBV serologic markers and quantitative HBV DNA were determined. Serum alanine aminotransferase (ALT) levels were measured to evaluate correlates of hepatocyte injury. A total of 64.6% of subjects demonstrated reactivity for any marker of current or past HBV infection or prior vaccination. Chronic HBV infection characterized by hepatitis B surface antigen (HBsAg) reactivity was present in 7.1% while 15.8% exhibited HB anticore IgG only. Approximately 10% of the latter group was HBV DNA positive by a polymerase chain reaction–based assay. Only patients with a serologic pattern of HBsAg or HB anticore alone reactivity had HBV DNA. Occult HBV was observed in approximately 10% of HIV-infected patients with HB anticore IgG antibody in a geographically representative national cohort. Though viral titers and serum ALT levels were low, screening of this subset of HIV-infected patients may have implications in terms of antiretroviral therapy and risk of immune reconstitution–associated flares.