Pasture grasses contain many secondary metabolites such polyphenols or vitamins that havedifferent health-promoting abilities in animals, including antioxidant effects. Pastures wouldprovide farmers the opportunity to contribute to animal health improvements with minimalinvestment. However, knowledge on the polyphenol content and antioxidant activity of pasturesis limited. The objective of this study was to assess the variability of polyphenol content andantioxidant activity (ORAC and DPPH assays) of 45 pastures located in three different areas ofFrance and chosen to represent a diversity of environmental conditions and botanical diversity.Important differences between pastures were observed: polyphenol content varied from 8.6 to40.8 mg of gallic acid equivalent per g dry matter (DM). Antioxidant activity varied from 9.1to 63.5 mg trolox equivalent per g DM with DPPH and from 50.9 to 280.3 mg trolox equivalentper g DM with ORAC. The present work provided a first valuable report on the potentialvariability in polyphenols and antioxidant activity of pastures. Next step will be to study thecorrelations between botanical diversity and pasture management and these values in order toimprove pastures utilization by taking account health benefits for ruminants.