Currently Poaceae species are the most commonly used herbaceous plants as food, feed and bedding for animals, raw material for biorefinery to produce fuels, power, heat, and value-added chemicals. The goal of this research was to evaluate the quality indices of the green mass, ensiled mass and hay from common oat Avena sativa as fodder for animals, as well as feedstock for the production of biomethane for renewable energy. The cultivar of common oat Avena sativa 'Sorin' created at the Agricultural Research and Development Station Lovrin and cultivated experimental field of the NBGI, Chisinau, served as subject of the research. The quality indices have been determined by near infrared spectroscopy technique, nutritional value and energy supply of the feeds and the biochemical methane potential of substrates were calculated according to standard procedures. The results revealed that the dry matter of whole oat plants contained 9.5% CP with forage value 598-603 g/kg DDM, RFV= 89, 11.84MJ/kg DE, 9.72-MJ/kg ME and 5.37MJ/kg NEl; prepared hay 10.5% CP, 574 g/kg DDM, 11.40 MJ/kg DE, 9.36 MJ/kg ME and 5.39 MJ/kg NEl. The ensiled forage (haylage) is characterized by pH = 3.77, 38.1g/kg lactic acid, 5.9g/kg acetic acid, 10.2% CP, 567-619 g/kg DDM, 11.28MJ/kg DE, 9.26MJ/kg ME and 5.29-MJ/kg NEl. The biochemical methane potential of the studied substrates from Avena sativa reaches 329-355 l/kg VS.