White-tailed deer (Odocoileus virginianus) populations in southern Québec have recently reached record densities after almost collapsing at the turn of the twentieth century. High densities of deer can dramatically alter forest vegetation and tend to increase use of tree plantations, orchards, and agricultural fields, which can induce severe financial loss to producers. We quantified grazing damage in young legume (i.e., clover [Trifolium sp.] and alfalfa (Medicago sativum]) fields that were bordered by woodlots near white-tailed deer wintering areas. We placed exclusion cages in 8 fields during two consecutive dormant seasons (October–May). We collected vegetation just prior to harvesting in exclusion and control plots to estimate dry biomass produced and legume, nitrogen (N), and fiber content of the hay. White-tailed deer grazing in autumn and spring caused an estimated loss ranging from 12–14% in subsequent annual yields in legume fields situated near woodlots. However, losses varied considerably among farms. Legume and chemical content (N and fibers) of the hay were not affected by grazing. Increasing deer harvest likely represents the best method to reduce damage to hay fields in southern Québec.