Breeding of temperate forage grasses is aimed at improving the economic and environmental sustainability of production from cattle and sheep. The primary objective is to ensure that forage can be the main source of feed for ruminants. This requires consistent production of herbage with a high feeding value, usually under nitrogen-limiting conditions. The most important traits affecting the feeding value of herbage are in vitro dry matter digestibility (DMD), the ratios of crude protein, water-soluble carbohydrate and fibre, and the concentration of alkaloid toxins. Improvements in these primary quality traits must be combined with good plant persistency, adequate tolerance to a range of environmental stresses, adequate resistance to a large number of different pathogens and invertebrate pests, and adequate seed yield. Forage grasses also have considerable potential to produce material for refining, to provide protein extracts for feeding to monogastric animals and carbohydrate for fermentation into fuel or into feedstocks for other industries.