Background: Cadmium (Cd), an environmental metallic toxicant with varying degrees of toxicity, exists in different oxidational or transitional states and causes various blood disorders. Cadmium (Cd) is known to affect various organs on both acute and chronic exposures. Studies have revealed that the most important tissue in body in which metabolic alterations are mainly reproduced is the blood. Moringa oleifera, originally from India, has been scientifically assessed for various medicinal applications. Aims and Objective: To examine the effect of M. oleifera aqueous extract taken from the leaf on total leukocyte count including its differentials (neutrophils and lymphocytes) in cadmium-treated rats. Materials and Methods: Twenty-four adult Wistar Albino rats, weighing between 180 and 200 g were broadly divided into four groups, six animals in each group, with group I being the control. Group IV was pretreated with the extract and then cadmium chloride orally for 1 day. Data were presented as mean ± SD and p p 0.05 considered significant. Result: The results portrayed that pretreatment with Moringa leaf extract, 100 mg/kg/bw, earlier to the cadmium administration exhibited a significant increase (p p 0.001) in the total leukocyte count including its differentials in comparison with the cadmium-exposed group, whereas the total WBC count was significantly decreased in group III in comparison with groups I and II. This study depicts a marked increase in the total leukocyte (T-WBC) count and its differentials in the animals pretreated with Moringa oleifera leaf extract, before the infusion of cadmium could be an indication that M. oleifera offers protection against damage to hematological parameters induced by cadmium. Conclusion: Therefore, our study suggests that aqueous leaf extract of M. oleifera enhances the immune mechanisms to fight back foreign substances when exposed to cadmium toxicity.