ABSTRACT Nilotinib (TasignaTM) a tyrosine kinase inhibitor is used in the treatment of chronic myelogenous leukemia and other tumor entities, this study aims to investigate nilotinib effects on fertility in male albino mice three groups each with 7 male albino mice selected, one control group, and two groups administered with 80mg/kg and 120mg/kg respectively for 3 months and serum levels of testosterone, FSH, and LH were measured by ELISA kits and statistically analyzed. Histological sections from testes prepared and stained with H&E stain and evaluated histopathologically. Statistically significant reduction in the mean of serum testosterone and FSH were seen in treated groups compared with the control group with no significant differences regarding LH concentration; variable histological changes noted in comparison with the control group ranging from mild changes in most cases with more severe atrophic changes in 1 case from the group(2) and 2 cases in a group (3).Our results showed statistically significant changes in testosterone and FSH levels in mice administered with nilotinib with variable deleterious histopathological changes