Abstract: The objective of this study was to determine the effect of non forage fiber sources in a total mixed ration on feed intake, nutrient digestibility, chewing behavior and ruminal fermentation. Five Brahman-Thai native crossbred steers with an average initial body weight of 188±16.56 kg were randomly assigned in a 5x5 Latin square design. During each of five 21 days periods, the animals were fed 5 total mixed rations that varied in the non forage fiber sources, rice straw as fiber sources (rt-TMR, control), tomato pomace as fiber source (tp-TMR), palm meal as fiber source (pm-TMR), dried brewer gain as fiber source (db-TMR), soybean hulls as fiber source (sh-TMR). The results showed that feed intake, crude protein digestibility, chewing time, total number of chew and ruminal fermentation were significantly different among treatments (p<0.05). The palm meal as a fiber source in the total mixed ration has negative effect on feed intake and chewing behavior, although enhanced by 5% of long hey fiber. However, tomato pomace, dried brewer gain and soybean hulls can be used as fiber sources in TMRs, when enhanced with 5% of long hey fiber.