This work seeks to analyze the carbon balance of a managed permanent grassland grazed by the “Blanc Bleu Belge” breed of cattle. The study site is located at Dorinne. The experimental field was equipped with an eddy covariance system that measured CO2 fluxes and with a micrometeorological station. Carbon exported through mowing, imported through compost application or through complementary feeds for cattle was also measured. Carbon lost through CH4 emissions was finally estimated, allowing the establishment of a full C budget. In addition, the vegetation development was followed in order to estimate herbage production and dry matter intake by grazing animals. First year full carbon budget is presented and discussed, in relation with climate conditions and management practices. ; Etablissement du bilan de carbone d’une exploitation agricole wallonne pratiquant le système allaitant : effets du climat et de la gestion du pâturage