Forage legumes are an essential component of agricultural systems in temperate regions of the world. Sainfoins (Onobrychis Mill.) are Eurasian legume perennial herbs, characterized by the highest condensed tannin content, provide beneficial effects and protect animals against bloat and increase protein absorption. In comparison with other species of fodder legumes, it is less demanding to the soil and if there is enough moisture in the soil, it produces high yields even in the poorest soils. We studied some biological peculiarities, the biochemical composition and the fodder value of a local ecotype of sand sainfoin, Onobrychis arenaria, grown in an experimental field of the National Botanical Garden (Institute), Chişinău. In the second growing season, the sand sainfoin was characterized by optimal growth rate and regenerative capacity after mowing, making it possible to cut it three times per season. It was established that the harvested green mass contained 169.6-264.5 g/kg dry matter. The concentration of nutrients in green mass dry matter was: crude protein 169.6-183.9 g/kg, crude fats 22.0-31.8 g/kg, crude cellulose 273.9-297.7 g/kg, nitrogen free extract 412.8 -447.2 g/kg, soluble sugars 34.4-73.2 g/kg, starch 15.9-23.3 g/kg, ash 74.1-83.6 g/kg, calcium 7.3-11.3 g/kg, phosphorus 2.5-2.7 g/kg, carotene 42.00-45.45 mg/kg. The hay prepared after the first and second cuts contained 163.8-167.9 g/kg crude protein, 16.5-17.0 g/kg crude fats, 315.2-366.7 g/kg crude cellulose, 377.1-413.7 g/kg nitrogen free extract, 75.5-83.6 g/kg ash, 7.7-9.9 g/kg calcium and 2.3-2.9 g/kg phosphorus, 7.86-8.66 MJ/kg metabolizable energy. The biochemical and the fodder value of the prepared haylages were: pH 4.75-5.16, lactic acid 51.5-53.0 g/kg, acetic acid 2.4-4.6 g/kg, butyric acid 0.3-0.4 g/kg, crude protein 164.9-174.9 g/kg, crude fats 26.127.4 g/kg, crude cellulose 278.2-300.3 g/kg, nitrogen free extract 428.9-439.3 g/kg, sugars 14.6-25.8 g/kg, starch 16.720.7 g/kg, calcium 9.3-9.9 g/kg, phosphorus 2.6-3.0 g/kg and 7.72-7.78 MJ/kg metabolizable energy.