This article reviews a previously published meta-analysis of 1264 titles or abstracts and 70 selected studies for evaluation of the efficacy of bacillus Calmette-Guérin (BCG) vaccine in preventing tuberculosis. Following review, data from 26 studies were included in the analysis. These 26 studies reveal that vaccination with BCG significantly reduces the risk of tuberculosis by an average of 50%. This level of protection persists across a number of subgroups defined by age at vaccination and study design. Vaccination with BCG was significantly associated with a reduction in the incidence of pulmonary tuberculosis and extrapulmonary disease. In general, the results of this meta-analysis lend weight and confidence to arguments favoring the use of BCG vaccine.