Mortality, particularly at younger ages, is a key measure of population health.To describe under 5 children mortality trends and its related factors in the Great Maghreb countries over the last three decades 1994-2019.We conducted an observational descriptive study to clarify the situation in the Maghreb countries with regard to the under-five death rates and the various causes related to them during the last three decades (1990-2019). The data was collected from the Global Burden of Diseases, Injuries, and Risk Factors (GBD).he overall trend for the five Maghreb countries was towards the decrease in the mortality rates for all age groups and for both sexes. Mauritania remains at the top of the list in term of the number of deaths followed directly by Morocco. The number of deaths of under-5 children is higher among boys in all Maghreb countries and the most affected age group is under 1 year old. Regarding the causes of under-5 mortality in Maghreb countries, the top-5 causes were similar; except in Mauritania where infectious diseases remain the leading under-5 mortality cause, like in other sub-Saharan countries.Despite the big drop in under 5 child Mortality rates, a lot remains to be done in Maghreb countries to improve children health.