Loss of agro-biodiversity is taking place at a high rate in Kenya. Many nutritious locally adopted indigenous species are being abandoned in favor of few exotic varieties. This has affected diets of preschool children; their diets are mainly starchy staples, little/no animal products and few fruits and vegetables. This book gives results of a cross-sectional survey to determine effect of agro-biodiversity on diet intake and morbidity of preschool children in Matungu Division, Western Kenya. Literature on loss in agricultural biodiversity, its effect on; diet diversity, nutrition status and immunity is reviewed. Methodologies describing study site, population, sampling, data collection and analysis are given. Results on state of agricultural biodiversity, diet diversity, nutrition status and morbidity of the preschool children are given. Relationship between the above mentioned variables are also well described. These results will shed light to researchers, government and non-governmental agencies aiming at enhancing food security and promoting better nutrition and health status of rural agricultural-dependent households.