Why did imitations of Raiffeisen's rural cooperative savings and loans associations work well in some European countries, but fail in others? This article considers the example of Raiffeisenism in Ireland and in the Netherlands. Raiffeisen banks arrived in both places at the same time, but had drastically different fates. In Ireland they were almost wiped out by the early 1920s, while in the Netherlands they proved to be a long-lasting institutional transplant. Raiffeisen banks were successful in the Netherlands because they operated in niche markets with few competitors, while rural financial markets in Ireland were unsegmented and populated by long-established incumbents, leaving little room for new players, whatever their institutional advantages. Dutch Raiffeisen banks were largely self-financing, closely integrated into the wider rural economy, and able to take advantage of economic and religious divisions in rural society. Their Irish counterparts were not.