This study was conducted to examine of rice straw after chemical treatments and ensiling on its feeding value, in situ studies using a rumen fistulated Korean cow and nylon bag technique. NaOH treatment greatly improved the degradation the Dry matter and Neutral detergent fiber degradation in the rumen but the intake was not affected. Ammonia treatment did not improve the degradation rate of rice straw in the rumen, but remarkably increased the rice straw digestibility and intake by sheep. Making silage of rice straw did not affect its rumen degradation rate, but the digestibility and its take by sheep were greatly improved especially when a little molasses together with Lactobacillus were supplemented. Degradation rate of rice straw in the rumen measured by nylon bag technique was influenced by various treatments but did not appear to coincide with digestibility by sheep. This would be due to the fact that feed intake affect digestibility as well as the degradation in rumen. Therefore, it can be said that making silage with some molasses and Lactobacillus is one of the easest way of using rice straw for animal feed. (Key words : NaOH, Digestibility, Silage, Molasses )