The metabolic pathways involved in hydrogen (H2) production, utilization and the activity of methanogens are the important factors that should be considered in controlling methane (CH4) emissions by ruminants. H2 as one of the major substrate for CH4 production is therefore should be controlled. One of the strategies on reducing CH4 is through the use of hydrogenotrophic microorganisms such as fumarate reducing bacteria. This study determined the effect of fumarate reducing bacteria, Mitsuokella jalaludinii, supplementation on in vitro rumen fermentation, CH4 production, diversity and quantity. M. jalaludinii significantly reduced CH4 at 48 and 72 h of incubation and significantly increased succinate at 24 h. Although not significantly different, propionate was found to be highest in treatment containing M. jalaludinii at 12 and 48 h of incubation. These results suggest that supplementation of fumarate reducing bacteria to ruminal fermentation reduces CH4 production and quantity, increases succinate and changes the rumen microbial diversity.