The present work aimed to identify the chemical composition of sugar cane bagasse (ScB), sugar beet pulp (SbP), stevia wastes (SW) and chicory pulp waste (CP) and also, to evaluate their nutritive value for animal feeding by using in vitro gas production technique. The potential of gas production technique is to predict fractions of rumen fermentable organic matter, kinetics of gas production, metabolizable and net energy, organic matter digestibility, short chain fatty acids and microbial protein were studied in some sugar -industrial by products and sweetener crops. A gas production was continuously measured by incubating samples in buffered rumen fluid from cannulated sheep for 96 h. Cumulative  gas production was recorded at 3, 6, 9, 12, 24, 48, 72 and 96 h of incubation periods and kinetics of gas production was described. The present results indicated a significant diversity in proximate composition and total phenolic content of the utilized agro-materials which play an important role on rumen fermentation. Analysis of sugar cane bagasse, sugar beet pulp, stevia wastes and chicory pulp waste revealed that crude protein, ether extract, ash, crude fiber and nitrogen free extract varied from 3.44 to 8.39%, 0.93 to 4.85%, 3.36 to 10.74, 15.82 to 42.39% and 49.88 to 71.32%, respectively. There were significant (P<0.05) differences among feedstuffs and some combination with hay and sugar cane bagasse in terms of metabolizable energy (ME) (8.121 vs 11.314 MJ/kg DM), net energy (NE) (4.068 vs 6.544 MJ/kg DM), short chain fatty acids (SCFA) (90.595 vs 137.215 mM), microbial protein synthesis (65.445 vs 89.366 g/kg OMD) and organic matter digestibility (OMD%) (54.667 vs. 74.1%).