The number of agri-environmental programs, as well as the share of agricultural land covered under these programs, varies significantly between EU member states. We analyze national differences in the uptake of agri-environmental programs by developing a model of countries' political objective function. Based on this model we identify six factors which may explain the extent to which agri-environmental policies are implemented: environmental benefits, opportunity costs of participation, financial budget pressure, the share of program expenditures financed by the EU, contribution to the EU budget, and political weight attributed to farmers' income. The conceptual approach is then supplemented by an empirical analysis.