The purpose of this study was to investigate the appropriate amount of oats to add to rice and the merits of oat meal. We analyzed the physicochemical characteristics, cooking properties, functional components, and sensory evaluation according to the amount of oats added in the cooked rice. Compared with rice, the oat showed higher level in protein, fat, total β-glucan and total polyphenol, but not for starch. Therefore, the amount of chemical and functional components was increased significantly with the increase in the amount of oats added. Water absorption and expansion were decreased with the increase in the amount of oat added. Oleic acid content was increased and linoleic acid content was decreased slightly. Unsaturated fatty acid content was greatly increased. The DPPH and ABTS radical scavenging activity were increased significantly according to the amount of oats added. As a result of sensory evaluation, the most appropriate amount of oat added was 20% and 30%. By the addition of oat, the β- glucan content of the cooked rice and the antioxidant activity could increase.