Objective: To investigate the antidiabetic properties of aqueous extract of stem bark of Afzeliaafricana (A. africana) and its beneficial effect on haematological parameters in streptozotocin induced diabetic rats. Methods: A total of 30 rats including 24 diabetic and 6 normal rats were used for this study. Diabetes was induced in male Wistar rats by intraperitoneal injection of streptozotocin. After being confirmed diabetic, animals were orally treated with distilled water or extracts at 100 or 200 mg/kg body weight daily for 10 days. The haematological parameters including red blood and white blood cells and their functional indices were evaluated in diabetic treated groups compared with the controls. Results: The extract significantly reduced the blood glucose levels while the best result was obtained at 200 mg/kg body weight. The feed and water intake in diabetic rats were significantly reduced while weight loss was minimized at both dosages. Similarly, the levels of red blood, white blood cells and their functional indices were significantly improved after extract administration at both doses. Conclusions: It can be concluded that the aqueous extract of bark of A. africana possesses antihyperglycemic properties. In addition, the extract can prevent various complications of diabetes and improve some haematological parameters. Further experimental investigation is needed to exploit its relevant therapeutic effect to substantiate its ethnomedicinal usage.