Because of the difficulty of confirming the diagnosis of childhood tuberculosis and because children do not make a significant contribution to the spread of tuberculosis, the burden of childhood tuberculosis in the world is uncertain. Several estimates make use of an arbitrary calculation assigning 10% of the tuberculosis burden to children. Available data linking the incidence of tuberculosis to the proportion of the tuberculosis caseload represented by children suggest an exponential rise in the proportion of the tuberculosis caseload caused by children as the tuberculosis incidence rises so that children may constitute nearly 40% of the caseload in certain high incidence communities. This review discusses the global burden of childhood tuberculosis and attempts to quantify this, the role of HIV/AIDS and tuberculosis in children, the problems this creates for diagnosis, and the occurrence of drug resistant tuberculosis in children. In the developing world, childhood tuberculosis is not under control, and, despite its importance as a child health problem, remains a neglected orphan disease.