Polymerase chain reaction (PCR) has been recently incorporated as a diagnostic tool for the diagnosis of tuberculosis. The benefit of rapid results and greater sensitivity compared with traditional microbiological methods makes PCR a suitable technique in childhood tuberculosis, especially when diagnosis is difficult or when urgent diagnosis is needed. However, the possibility of false-positive results must be considered, especially if the clinical and epidemiologic context of the child make the diagnosis of tuberculosis improbable. The commercial 'Amplicor PCR test' lacks good sensitivity and specificity and it would be necessary to develop other commercial easy-to-use PCR kits that provides better yield.