Hospital Dom Rodrigo Jose de Menezes. Salvador de Bahia. The Director of the center does not know how many people are internal. Former patients whose families do not exist or do not take care of them or do not have the necessary resources. They eat, sleep, receive medication. In this study we evaluated the protective effect against leprosy vaccination with BCG by case-control study. We selected 97 patients under 16 diagnosed with leprosy (cases) and 385 healthy people (controls) who were matched by sex, age, place of residence and type of contact (intra-or extradomiciliary). The cases were selected from active records of leprosy patients and a series of incidents leprosy cases treated at 50 centers in the city of Sao Paulo, Brazil. To estimate the protective effect of BCG, we compared the prevalence of BCG scars of cases and controls. The presence of one or more scars was associated with a protective efficacy estimated 90 percent confidence interval (95 percent-78 percent-96 percent). Stratified analysis by age, sex, socioeconomic status and clinical form of leprosy showed no significant differences in vaccine protection. We analyze the significance of these findings and the relevance of using the BCG in the programs of leprosy control