**Abstract**

This chapter aims to describe the strategies implemented by the Ministry of Health since 2004 to reduce deaths classified as ill-defined causes (IDC) and the impacts on the mortality profile. Since 1979, deaths occurring and recorded across the country have been stored electronically on the Datasus website (www.datasus. gov.br), which is in the public domain. From this database, it appears that the proportion of deaths from IDC in the country decreased from 20.1% in 1979 to 5.5% in 2017. In small municipalities, less than 20,000 inhabitants, which have the worst data quality and worse socioeconomic status and with the greatest inequities in health, requiring greater investments, the reduction was smaller. The Ministry of Health implemented several actions that involved suspending the transfer of resources from the federal fund to the municipal fund for non-compliance with the rules for the collection, flow and periodicity of information on deaths, in addition to training and qualification of human resources to record and code the causes of death and to investigate deaths by IDC through verbal autopsy. These are initiatives that can be replicated in other contexts, except, perhaps, of a legal nature, as they fit into the legal system that presents specificities in each country.

**Keywords:** ill-defined causes, mortality information system, mortality statistics, basic cause of death, mortality, time trend, mortality profile
