Forage samples from Stipa caphillata-Cleistogenes squarrosa communities from the Eastern Mongolian rangelands were analysed for chemical composition and digestibility. Samples were collected at 10-days intervals from 30th June to 10th September. The study indicated that OM content of Stipa caphillata-Cleistogenes squarrosa communities ranged from 94.4 to 95.2%. The highest value (10.2%) of CP was found at the end of June, the lowest value (8.0%) was found in September. Forage NDF and ADF ranged from 61.4 to 66.1%, and from 36.8 to 39.6%, respectively. DMD ranged from 66.5 to 71.9%. Cumulative in vitro gas production during 70 h fermentation of forages ranged from 243.6 to 276.1 ml/g. A year old standing dead of these communities has showed similar nutritive value as that of cold season straw hay.