The College of Science discussed a master’s thesis tagged with the biological manufacture of nanoparticles of iron oxide using the aqueous extract of custard fruit and testing the inhibitory effect against the anterior flagellates of the Leishmania tropica parasite, by student Ahmed Mahdi Barghash, and supervised by the Dean of the College Prof. Dr. Nima Ali Ahmed and Prof. Dr. . Faten Muhammad Nawab Al-Din. The study included the bio-manufacturing of magnetic iron oxide nanoparticles in a biological way using the aqueous extract of the peel of the cream fruit, and its detection by various methods, including X-ray diffraction (XRD) analysis, FT-IR spectroscopy, transmission electron microscopy (TEM) and electron microscopy. Scanning SEM and EDX spectroscopy, evaluating the inhibitory activity of the manufactured nanoparticles against the frontal promastigotes of Leishmania tropica in the laboratory, and their effect on the generation time and number of generations, and determining the minimum and maximum inhibitory concentration of the particles, as well as showing the effect of the nanoparticles on the total protein concentration The study aimed to find out the effect of high concentrations on reducing the number of generations, while there was an increase in generation time by increasing concentrations during growth periods with a decrease in the amount of protein when using the minimum inhibitory concentration of 20 μg / ml. The study concluded that the iron oxide nanoparticles manufactured by this method Bioavailability has a toxicological activity and variable effect through the use of different concentrations (10-40 μg / ml) in the Anterior flagella of L. tropica during (96) hours of growth.