In vivo glycemic index using maize and kidney bean composite flour was carried out by applying cutoff value of greater than seventy (>70) to denote a high glycemic foods, 55-69 indicating medium glycemic foods and (<55) and below indicating low glycemic foods. Maize and kidney bean flours were obtained using the ratios A= (100 maize flour as control), B= (90 MF and 10% KBF), C= (85 % MF and 15% KBF), D= (80% MF and 20% KBF) and E= (75 % MF and 25% KBF). Products were analyzed for glycemic index using albino rats, full Amino acid profile, mineral and vitamin analysis. The glycemic analysis showed a decreased in the fortified samples against the control as the level of kidney bean flour substitution increased over time. There was also a considerable increase in the chemical analysis as the level of kidney bean flour increased. The chemical analysis showed increment in their respective ratios as the level of substitution increased. Results reviewed the problem of poor malnutrition in developing countries and provide a balanced meal. Practical Application Glycemic index (GI) is a measure of the blood glucose-raising potential of a carbohydrate-containing food after it is eaten. Substitution of kidney beans with maize flour can be used to improve the nutrient composition, blood glucose level for diabetic patients and other quality attribute as the fortified samples showed a positive effect on the reduction of blood glucose level. The results of the study also showed maize and kidney bean flours will help to reduce incidences of protein energy malnutrition in the world especially in developing countries.