Tuberculosis in children is a growing problem, both globally and in many industrialized countries. With a rising incidence, clinicians will again face the challenge of the myriad presentations of tuberculous disease. Multidrug resistance and HIV coinfection present additional complications. Renewed interest in tuberculosis among scientists has led to progress in our understanding of antimycobacterial effector mechanisms, the regulation of Th1 and Th2 immune responses, virulence factors, and the potential for immunotherapeutic agents to reduce the duration of antituberculous therapy.