Recent works on economic voting have shown that the economy's impact on electoral behaviour could sometimes be mediated by differences in political conditions. This article specifies and tests the mediating role of one such factor, namely regionalism, on economic voting in Canada. The potential effect of two structural factors is tested: the regional configuration of the federal party system (clarity of available alternatives), and the regional structure of the economy. The data used come from the last four Canadian Election Studies (1988 to 2000). The results show that economic voting slightly differs among regions according to the presence or not of strong regional political parties, Quebec being the region where the relationship between the economy and the vote is the weakest. Even more significant differences in economic voting behaviour can be observed between ''have'' and ''have not'' regions, the shape of economic voting in the Atlantic provinces being distinct from the one in Ontario and the West.