The proportion of the starch that escapes rumen degradation varies from 5 to 65% of the starch intake. It depends on the feeding level and the nature of the cereal, and for a same cereal, on its endosperm hardness, related to genotype and maturity, and on the technological treatments, including particle size (Huntington et al., 2006). The intestinal digestion of starch escaping rumen degradation essentially takes place in the small intestine and varies between 15 to 85% of the starch that arrives into the duodenum. As in the rumen, this variability would essentially be due to the intrinsic features of the maize that determines the accessibility of the starch to the endogenous enzymes, in particular the endosperm hardness and the particle size. The aim of this work was to evaluate the rumen starch degradation of maize and its residue digestion in the small intestine as function of particle size and endosperm hardness.