Abstract: Chlorpyrifos (CPF) toxicity has been shown to be partly mediated through induction of oxidative stress. In the present study, experiments were conducted with the aim of evaluating the ameliorative potentials of zinc on CPF-evoked alteration in hematological parameters in Wistar rats. Twenty adult male Wistar rats were divided at random into 4 groups of 5 animals per group. Rats in group I served as the control and were given only soya oil (2 mL kg-1) while those in group II were administered zinc only (50 mg kg-1). Rats in group III were dosed with CPF only (10.6 mg kg-1, ~1/8th of LD50). Those in group IV were co-administered zinc (50 mg kg-1) and CPF (10.6 mg kg-1). The different regimens were administered orally once daily for a period of 8 weeks. At the end of the study period, blood samples collected after sacrificing the animals were analyzed for hematologic parameters such as Packed Cell Volume (PCV), Hemoglobin (Hb), Red Blood Cells (RBC), Mean Cell Volume (MCV), Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC), hemoglobin indices, platelets, absolute and differential White Blood Cell (WBC) counts, neutrophil-lymphocyte ratio and erythrocyte malonaldehyde (MDA) concentration. The results revealed that alterations in the values of PCV, Hb, RBC, platelets, absolute and differential WBC and MDA induced by CPF were ameliorated by co-administration with zinc. In conclusion, the study has shown that attenuations of CPF-evoked alterations in hematological parameters by zinc may be partly mediated through its antioxidant properties.