This study aimed to identify new drug molecules against Leishmania parasites, leishmaniasis's causal agent, using Pistacia atlantica leaves as source. The evaluation of the anti-leishmania potential against the promastigote form of Leishmania. infantum and Leishmania. major was performed. A new in silico study was accomplished using molecular docking, with Autodock vina program, to find the binding affinity of two important phytochemical compounds from this plant (Masticadienonic acid, 3-Methoxycarpachromene) towards the trypanothione reductase as target drugs, responsible for defence mechanism against oxidative stress and virulence of this parasites. Results: Several concentrations showed a significant decrease in cell viability (P<0.0001), with IC50 values of 0.3 mg/ mL for L. infantum and 0.12 mg/ mL L. major; The molecular docking confirms the significant relationship between Leishmania survival and the inhibition of this crucial enzyme. There were promising and new positive results on binding modes of selected ligands and the trypanothione reductase for the first time. Through this work, we propose 3-Methoxycarpachromene and Masticadienonic acid as anti Trypanosomatidae species drug.