The present study was to evaluate the anti-anemic power of total aqueous extract of Moringa oleifera leaves (TAEMo) on phenylhydrazine induced anemic Wistar rats. First, hemolytic anemia was induced in rats by intraperitoneal administration of phenylhydrazine (PHZ) at the dose of 40 mg/kg body weight for two consecutive days. Then, the anemic rats were orally treated daily for 26 days with aqueous extract of Moringa oleifera leaves (TAEMo) at doses of 400, 800 and 1600 mg/kg b w. and Ranferon®-12(Reference substance). The rats were analyzed for erythrocyte parameters such as erythrocyte cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration on day 0, 2, 5, 14 and 28. The results revealed that the aqueous extract restored rapidly the modified erythrocyte parameters at the end of treatment. TAEMo at 1600 mg/kg showed an effect similar to the reference substance, Ranferon®-12. The study of reversibility after stopping treatment showed that not all erythrocyte parameters studied were significantly affected. This study found anti-anemic properties of Moringa oleifera leaves aqueous extract thus confirming the use of this plant in the treatment of anemia in the population.