BackgroundAmong adults with advanced HIV infection in developing countries, bacteremia due toMycobacterium tuberculosis(MTB) is common and bacteremia due toM. bovis(bacille Calmette–Guérin; BCG) is rare. Comparable data are not available for children with HIV.ObjectiveTo compare the prevalence of bacteremia due toM. tuberculosisorM. bovisBCG in hospitalized children and adults with HIV infection in a developing country with a high prevalence of tuberculosis and HIV and > 95% BCG immunization coverage.DesignDescriptive cross-sectional study.MethodsProspectively hospitalized patients in Lusaka, Zambia who were suspected to have HIV infection underwent phlebotomy for HIV ELISA, HIV viral load, and lysis-centrifugation blood culture for mycobacteria. Histories were obtained and patients were examined for BCG scars. Mycobacterial isolates were identified using DNA probes for MTB complex (MTBC), multiplex PCR and IS6110typing.ResultsThe median age of 387 HIV-positive children was 15 months; 98% were BCG immunized. The median age of 344 HIV-positive adults was 32 years; 44% were BCG immunized. Blood cultures were positive for mycobacteria in six children (2%) and 38 adults(11%) (P< 0.001). The six pediatric isolates included five MTBC (40% clustered) and one BCG. The 38 adult isolates included 36 MTBC (16% clustered) and twoM. aviumcomplex.ConclusionBacteremia due to MTB is less common among children than adults with advanced HIV infection in Zambia. Bacteremia due toM. bovisBCG is rare even among children with recent BCG immunization and symptomatic HIV infection.