In view of the limitations of survey-based demographic techniques for infant mortality estimation, the current strategy of some developing countries is to improve vital information. This article presents recent progress in the improvement of national databases in Brazil.For the vital information analysis, the data sources are the Mortality Information System and the Live Birth Information System. The adequacy analysis is based on five indicators calculated at the municipality level per 3-year period. Adequacy criteria are established by means of the indicator percentile distributions among Brazilian municipalities. To complement the vital data analysis, in 2001, a proactive search of infant deaths was carried out in selected areas of the North and North-east with very deficient information.Temporal trends of the adequacy indicators indicate advances in both information systems. In 2003-05, 80.3% of municipalities (87.3% population) have adequate live birth data and 63.6% of municipalities (77.9% population) have a satisfactory level of mortality information. The most important problem refers to deaths with undetermined causes, mainly in the North-east. The proactive search of infant deaths showed large deficiencies of vital information in areas of extreme poverty: from 520 infant deaths found in the study, only 175 (33.7%) were reported to the Mortality Information System.The monitoring of vital events is an essential step in the process of reducing infant mortality. The analysis of local irregularities not only improves the quality of vital data registration, making possible to estimate the infant mortality rate, but also identifies priority areas for intervention.