Background: Paullinia pinnata is a medicinal plant used for the treatment of various diseases, including anemia in West Africa. Aim: This study was carried out to investigate the effect of increasing doses of the methanolic leaves extract of P. pinnata on hematological parameters in rats. Materials and Methods: Thirty‑six male Wistar albino rats were grouped into six groups of six animals each. Five doses; 50,100, 200, 400 and 800 mg/kg body weight of the P. pinnata extract were administered separately to five groups. The sixth group served as a control and received only the vehicle (70% physiological saline: 30% Tween 80 [v/v]). Administration was done orally daily for 28 days at 24 h interval. On day 29, the animals were made inactive, blood was then collected from the heart and various hematological parameters were evaluated. Statistical Analysis: Analysis of variance was employed. Results: The packed cell volume and red blood cell count increased significantly (P < 0.05) in the treatment groups except at 200 mg/kg dose. The hemoglobin concentration increased in all the treatment groups. The values for the neutrophils at 50, 100, 200 and 800 mg/kg doses were higher than that of the control. The white blood cell count increased significantly (P < 0.05) at 50 and 400 mg/kg doses compared to the control and exceeded the normal physiological range. Conclusion: The maximum tolerable dose is 200 mg/kg body weight of the methanolic leaves extract of P. pinnata and the extract has anti‑anemic property with the ability to increase neutrophils count.