At the European scale, grassland classifications and policies are mainly based on a phytosociological approach. However, agronomists use other classifications, such as agronomical typologies, indicators, models, measurements of forage yield or quality. Grasslands in the Vosges Mountains (north-eastern France, 170 - 1,424 m a.s.l., 7,000+ km²) have been studied following these two approaches in the last few years. Are these methods redundant or complementary? We compared a phytosociological classification made by botanists based on a sample of 550 grasslands and an agronomical classification from the study of 233 grasslands. This work didi not show equivalences between the two approaches: the prediction of grasslands' ecological and agronomical values requires the association of both approaches. We, therefore, propose that current grassland classifications need both agronomical and phytosociological criteria in order to provide complete information on ecosystems and sustainable production.