This article examines the impact of endowments, property rights and political conflict on the diffusion of cream separators in late nineteenth-century Ireland. Favourable endowments, access to finance and owner-occupancy promoted the spread of cream separators, while in areas with more small farms political conflict slowed down the diffusion of separators as well as of cooperatives. The structure of property rights and political conflict help explain why Irish agriculture was less successful than Danish agriculture during this period.