This paper modelled the participation decision of Irish farmers in an agri-environmental scheme. It also uses the sub sample of farmers in the National Farm Survey actively participating in the scheme in 2007 to model the various biodiversity options undertaken as a function of farmer demographic characteristics, farm characteristic and habitat variables. The results of the analysis demonstrate that younger, married farmers with larger farms are more likely to participate in REPS and that the voluntary aspect of REPS can mean that not all habitat types are equally likely to be covered by the scheme. Farmers with internationally important habitats on their farm, like intact peatlands or semi-natural grasslands are more likely to participate in REPS. However, there is evidence to suggest that these farmers are choosing to participate in REPS because they view their land as having low economic value rather than having high ecological value. Farmers with water or wetland and forest are less likely to participate in REPS, which indicates that some important ecosystems may not be included in the scheme. The 1 biodiversity options undertaken by the farmers are found to facilitate the management of the system of farming on the holing rather than the type of habitats on the land.