The effects of the intake of flour obtained from mango pulp (Tommy Atkins cultivar) (6.85% soluble fiber, 11.96% insoluble fiber, 2.53% protein, 1.3% total lipids and 2.52% ash) on weight gain, dietary intake, glycemia and hepatic glycogen were studied in normal and diabetic rats. The diabetic animals eating diets containing 5, 10 and 15% mango flour during the 30 day study showed a significant decrease (p < 0.05) in blood glucose level in comparison to the diabetic controls eating a diet containing 0% mango. In the second study, diets with 0 and 5% mango flour were fed to diabetic rats to see if the 5% mango diet would still reduce blood glucose over a longer period. The blood glucose level of the rats consuming mango at the end of ninety days was 66% lower than that in the controls. In this study, it was also observed that the hepatic glycogen level of the animals fed mangos was 64% greater than in the controls, which might have contributed to the reduction in blood glucose in these animals. In addition, the animals fed mango had a higher serum insulin level (p < 0.05) than those in the control group. The results from this research suggest that mango flour can possibly help in the treatment of diabetes.