OBJECTIVESTo estimate tuberculosis (TB) rates among young children in the United States by children's and parents' birth origins and describe the epidemiology of TB among young children who are foreign-born or have at least 1 foreign-born parent.METHODSStudy subjects were children <5 years old diagnosed with TB in 20 US jurisdictions during 2005-2006. TB rates were calculated from jurisdictions' TB case counts and American Community Survey population estimates. An observational study collected demographics, immigration and travel histories, and clinical and source case details from parental interviews and health department and TB surveillance records.RESULTSCompared with TB rates among US-born children with US-born parents, rates were 32 times higher in foreign-born children and 6 times higher in US-born children with foreign-born parents. Most TB cases (53%) were among the 29% of children who were US born with foreign-born parents. In the observational study, US-born children with foreign-born parents were more likely than foreign-born children to be infants (30% vs. 7%), Hispanic (73% vs. 37%), diagnosed through contact tracing (40% vs. 7%), and have an identified source case (61% vs. 19%); two-thirds of children were exposed in the United States.CONCLUSIONSYoung children who are US born of foreign-born parents have relatively high rates of TB and account for most cases in this age group. Prompt diagnosis and treatment of adult source cases, effective contact investigations prioritizing young contacts, and targeted testing and treatment of latent TB infection are necessary to reduce TB morbidity in this population.