The objective of this study was to determine the effect of non forage high fibrous feedstuffs as fiber sources in a total mixed ration on gas production characteristics and in vitro fermentation using an in vitro gas production technique. The experiment was designed in CRD with five replicates per treatment. The fiber sources in the total mixed ration were rice straw (rt-TMR), tomato pomace (tp-TMR), palm meal (pm-TMR), dried brewer gain (db-TMR) and soybean hulls (sh-TMR). The results showed that kinetic gas production, in vitro dry matter digestibility and in vitro organic matter digestibility, were significantly different among treatments (p<0.05). The soybean hulls as a fiber source in the total mixed ration gave the highest IVDMD, IVOMD and gas production parameter. In vitro fermentation end-products consisting of NH3-N, TVFA and pH were significantly different among the treatments (p<0.05); however, the pH values were relatively stable at 7.01-7.16. All treatment means were within the normal range. NH3-N concentration was in the optimal range for rumen ecology microbial activity. Future research should investigate the impact of the ability of non forage high fibrous feed to replace forage in intact animal.