Malnutrition includes both under- and over-nutrition. The development of rice varieties to improve dietary quality can play a role in addressing both forms of malnutrition. This chapter begins by considering under-nutrition, with an emphasis on the problem of micronutrient deficiency. It reviews how a staple crop such as rice can be biofortified to deliver key nutrients such as iron, zinc and vitamin A. Over-nutrition and its negative health consequences are then discussed, and we explore the possibility of biofortifying rice to carry nutritional properties of benefit to those at risk of or suffering from chronic disease.