Bait-marking is a widely used technique for determining the territorial configuration of social groups of the European Badger (Meles meles). Applications include ecological research and applied wildlife management problems. Bait laced with indigestible plastic pellets is fed to Badger social groups, and the markers are identified in subsequent defecations. Feeding a unique colour and/or shape of pellet to each social group allows the origin of droppings to be assigned. This method is particularly suited to Badgers because they mark their territorial boundaries with communal latrines. In this paper the technique is described in detail for the first time in the scientific literature. Data from sequential visits to latrines during the survey period showed significant short-term variation in the number of marked droppings counted at individual latrines. This suggests that counting marked droppings may be of limited value in quantifying defecation rates and latrine use. However, counts of droppings at latrines could be useful if repeated over time and/or grouped into broad categories. Bait marking does provide reliable data for the estimation of territorial boundaries between Badger groups, although it is labour intensive and time-consuming, with the best results obtained by experienced fieldworkers.