In an effort to develope a corn bran-based concentrate feed for growing Korean cattle, corn bran was used at the levels of 50%, 40, and 30% and the rest was supplemented with proper nutrients. Energy and nitrogen were supplemented with corn starch, molasses, corn germ meal and urea. Vitamines and mineral sources were also added in the mixture. As a preliminary step of evaluating the feeding value of these corn bran feed, an in vitro fermentation and an in vivo digestibility experiment were conducted. The results obtained were as follows 1. During the first 12 hours of in vitro fermentation production of acetic, propionic and butyric acid from the feed containing 50% corn bran was significantly (P$lt;0.05) lower than the control or other cornbran feeds. However, after 24 hours of fermentation there was no difference in the production of these acids except acetic and propionic acid that were significantly (P$lt;0.05) higher for the feed containing 30% corn bran than other. 2. Digestibility of crude fiber and ash was higher and ether extract v, as lower for the corn bran feeds than the control feed in general. As the corn bran level was lowered, digestibility of crude protein and nitrogen free extract was increased but digestibility of crude fiber and ether extract was decreased. 3. Total digestible nutrients (TDN) of the control, the feeds containing 50%, 40% and 30% corn bran were 56.68, 55.59, 58.02 and 58.27%, respectively. As the corn bran level was lowered, digestible nitrogen free extract was increased and that made TDN value higher but significantly lowered digestible crude fiber of the feed containing 30%, corn bran made its TDN value similar to that of the feed containing 40% corn bran. 4. During the collection period of the digestion trial, fecal excretion of nit rogen was lowest for the feed containing 30 % corn bran but urinary excretion of nitrogen was highest for the diet containing 50% corn bran. Nitrogen retention was about 12.0% of intake for the diet containing 50 % corn bran and about 20.0 % for the rest corn bran feeds and control feed. 5. Over all results, considering the fact that the digestibility of crude fiber was depressed and scouring problem was observed with the diet containing 30% corn bran, indicate that corn bran can be succesfully used at the level of 40% on more in a corn bran-based concentrate mixture for cattle feeding.