ABSTRACT:Objective: To analyze under-5 mortality rates and leading causes in Brazil and states in 1990 and 2015, using the Global Burden of Disease Study (GBD) 2015 estimates. Methods: The main sources of data for all-causes under-5 mortality and live births estimates were the mortality information system, surveys, and censuses. Proportions and rates per 1,000 live births (LB) were calculated for total deaths and leading causes. Results: Estimates of under-5 deaths in Brazil were 191,505 in 1990, and 51,226 in 2015, 90% of which were infant deaths. The rates per 1,000 LB showed a reduction of 67.6% from 1990 to 2015, achieving the proposed target established by the Millennium Development Goals (MDGs). The reduction generally was more than 60% in states, with a faster reduction in the poorest Northeast region. The ratio of the highest and lowest rates in the states decreased from 4.9 in 1990 to 2.3 in 2015, indicating a reduction in socioeconomic regional disparities. Although prematurity showed a 72% reduction, it still remains as the leading cause of death (COD), followed by diarrheal diseases in 1990, and congenital anomalies, birth asphyxia and septicemia neonatal in 2015. Conclusion: Under-5 mortality has decreased over the past 25 years, with reduction of regional disparities. However, pregnancy and childbirth-related causes remain as major causes of death, together with congenital anomalies. Intersectoral and specific public health policies must be continued to improve living conditions and health care in order to achieve further reduction of under-5 mortality rates in Brazil.