Visceral leishmaniasis (VL), the second-most-serious parasitic illness after malaria, is currently endemic in more than 88 countries. Need for new anti-leishmanial compounds is currently being taken into consideration by researchers due to resistance and lack of effective vaccinations. This research was conducted to find out more about the effect of artemisinin (ART). ART was examined in vitro promastigotes stages and ex vivo amastigotes stages of the Iraqi strain of Leishmania donovani in U937 cell line after 24, 48 and 27 hours using MTT assay. In addition, the level of macrophage nitric oxide (NO) was measured using Griess assay in U937 cell line. The results of promastigotes viability percentage