This research was conducted to determine the chemical composition of crested wheatgrass in artificial pasture from the years 2010 to 2012. The mixture of the pasture used were alfalfa (Medicago sativa L.) + sainfoin (Onobrychis sativa Lam.) + crested wheatgrass (Agropyron cristatum L.) + smooth bromegrass (Bromus inermis L.). Forage samples were collected from grazing and non-grazing areas once every 15 days during the grazing seasons. The crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) contents, in vitro dry matter digestibility (IVDMD), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg), ratios were determined on the crested wheatgrass forage samples. According to results, CP, IVDMD and K contents decreased throughout the grazing season, while ADF and NDF contents increased in grazing areas. In non-grazing areas, the CP content, IVDMD, Mg, P and K contents decreased throughout the grazing season, while ADF, NDF and Ca contents increased. The ADF, NDF, Ca contents of crested wheatgrass in non-grazed areas were higher than the grazed areas, while CP, IVDMD, P, Mg and K contents of grazed areas were higher than non-grazed areas. It can be concluded that the harvesting at the late stages caused a reduction in forage quality of crested wheatgrass in grazing and non-grazing areas.