Cereal-based food products have been the basis of the human diet since ancient times. Dietary guidelines all over the world are recommending the inclusion of whole grains because of the increasing evidence that whole grains and whole-grain-based products have the ability to enhance health beyond the simple provision of energy and nutrients. In this review we will examine the main chemical components present in whole grains that may have health enhancing properties (dietary fiber, inulin, beta-glucan, resistant starch, carotenoids, phenolics, tocotrienols, and tocopherols) and the role that whole grains may play in disease prevention (cardiovascular diseases and strokes, hypertension, metabolic syndrome, type 2 diabetes mellitus, obesity, as well as different forms of cancer). The knowledge derived from the functional properties of the different chemical components present in whole grains will aid in the formulation and development of new food products with health enhancing characteristics.