BACKGROUND AND OBJECTIVES: We aimed to calculate the change in under-5 mortality rates (U5MRs) , to assess countries' status regarding Sustainable Development Goal (SDG) 3.2.1 (reducing the U5MR to #25 deaths per 1000 live births by 2030), to list the most important causes of death (1990, 2016), and to examine the association between selected SDG indicators and U5MRs using a linear mixed-effects regression.METHODS: Ecological study in which we used estimates from the Global Burden of Disease Study 2016 for Central American countries. Results were expressed as U5MRs (deaths per 1000 live births), cause-specific mortality rates (deaths per 100 000 population ,5 years of age), and regression coefficients with 95% confidence intervals.RESULTS: U5MRs decreased 65% , and in 2016, all countries but Guatemala had met SDG 3.2.1. The main causes of death were diarrheal diseases (1990; 311.1 per 100 000) and lower respiratory infections (LRIs) (2016; 78.1 per 100 000). When disaggregated by country (2016), congenital birth defects were the most important cause of death in all countries except for in Honduras (neonatal preterm birth) and Guatemala (LRIs). Nutritional status; availability of water, sanitation, and hygiene services; coverage of vaccines; and coverage of contraception were associated with a reduction in U5MRs.CONCLUSIONS: Central America has achieved a large reduction in U5MRs. Countries must address both the high mortality caused by LRIs and the rising mortality caused by noncommunicable causes of death through an improvement of SDG indicators that guarantees equitable progress in child survival in the region.WHAT'S KNOWN ON THIS SUBJECT: Changes in under-5 mortality rates have been reported in Central America, ranging from 39% (Panama) to 75% (El Salvador) (1990-2011 study). Vaccination coverage was related to a reduction in child mortality in a study including countries from the region.WHAT THIS STUDY ADDS: This study highlights the need for addressing the high mortality resulting from communicable causes of death and the rising mortality resulting from noncommunicable causes in Central America by improving different components of the Sustainable Development Goals framework.