The aim of this study, was to assess the nutritive value of some legumes forage species commonly used for feeding livestock in Turkey using the chemical composition including tannin, in vitro gas production and in vitro Dry Matter (DM) digestibility. There was wide variation in tannin content ranging from low, moderate to high especially in CO, CPW, DP, A, LCT, LA, LCV. A cumulative gas production, kinetics of gas production, ME, OMD, NH3-N and VFA concentrations were determined. The CP was ranged on average from 132-193 g kg-1 DM. As for ash content, the highest value was observed with Lotus corniculatus (130.2 g kg-1 DM) and the lowest value was 62.5 g kg-1 DM for DP. The highest (p<0.05) value of potential degradability (a+b) was estimated with LCV. The lowest (p<0.05) value of a+b was observed by LA. There was no significant (p>0.05) difference among all speices roughages for VFA concentration in rumen fluid. ME, OMD, CT content, WSC, NH3 -N values were significantly (p<0.05) different among all legumes species, but there was no significantly (p>0.05) difference for pH among all legumes in rumen fluid. The present study concluded that different legumes of Turkey as good quality roughages and has potential as alternative animal feed resources for ruminants based on chemical composition, gas production and OMD, the legumes species forages have high potential nutritive value especially as protein sources. However, the presence of tannins in some of the legume species forages may adversely affect their potential nutritive value. Because significiant negative correlations between content of condensed tannin and gas production (total gas production mL/144 h) and OMD, ME showed significant negative correlations (r2: -0.867; r2: -0.883; r2: -0.882, p<0.001), respectively observed. © Medwell Journals, 2008.