This experiment was carried out to determine and compare the chemical composition, digestibility and gas production of grain ofVicia sativa, Lathyrus sativus and Vicia ervilia cultivated in Ardabil province. Digestibility was estimated using in vitro methods. The gas production was recorded after 2, 4, 6, 8, 12, 24, 48, 72 and 96 h of incubation. Crude protein content of legume grains were in range of 23.89-29.34%/DM, NDF (31.12-36.63%/DM) and digestible dry matter (71.86-84.93%). Among the tested grains, the grain of Vicia ervilia had highest fermentation parameters, potential gas production and rate of gas production, Short Chain Fatty Acids and metabolizable energy that estimated as 80 mL in 200 mg sample, 0.103 mL h-1, 1.506 mmol, and 11.72 MJ/kg respectively and Vicia sativa grain had the lowest potential gas production (72.18 mL in 200 mg sample), rate of gas production (0.083 mL h-1), Short Chain Fatty Acid (1.313 mmol), and metabolizable energy (10.35 MJ/kg) content. The grain of Vicia ervilia, had higher nutritive value than other tested feeds due to its in vitro fermentation characteristics as well as chemical composition. It was concluded different test feeds had different chemical composition, in vitro digestibility, gas production and metabolizable energy which significantly affected the degradation parameters.