Abstract : Objective: to study under-five mortality trend and top killers in Basrah Governorate, Iraq for 2012-2018. Methods: This is a descriptive, retrospective study implemented during the period from 15th of March 2020 to 30th of December 2020 in Basrah Governorate to study under-five mortality rates time trend for the years 2012-2018 included all under-five registered deaths. A sample of 1000 death certificates is taken to elicit neonates top ten killers. Results: In general, for targeted years under-five mortality rate and infant mortality rate dramatically decreased while the neonatal mortality rate took slight decrease. Male under-five mortality rate was more than female under-five mortality rate. The majority of deaths occurred in hospital in comparison to house and other places. First killer disease in neonates was newborn respiratory distress. Conclusion: Under-five mortality rates shows dramatic decrease for 2012-2018. Mainly in the neonatal period, the majority of deaths occurred in infanthood. Key words: Under-five, mortality, rate, trend, top killers, Iraq, Basrah.