This experiment was conducted to evaluate the efficacy of daily feeding a live microbial preparation containing live organisms fed to finishing cattle. Additions of live organisms to the rumen are thought to improve the fermentation and overall digestion. Three strains of a lactobacillus and a propionibacterium were studied in this experiment. The study was conducted with Angus steers with an average initial weight of 625 lbs and fed a finishing diet containing on a dry basis 30% wet corn gluten feed, 60% rolled corn, 8% chopped hay and 2% supplement for 174 days. Feeding the microbial product being marketed for feeding cattle improved daily gain and feed efficiency 2.2% and 1.1%, respectively, but the differences were not statistically significant. The microbial preparation increased carcass weights 1.1% and tended to increase carcass fat. Use of different strains of lactobacillus with the propionibacterium did not improve performance or affect carcass grades. It is concluded that potential benefits of feeding the live microbial product may be somewhat less when a portion of the corn is replaced with corn gluten feed.