Rogowski and Kayser posited that electoral systems, because they modify the balance of consumer-producer power, also modify price levels.  Cross-sectional analysis of OECD countries in 1990 indicated that majoritarian electoral systems lower real price levels by approximately 10 percent.  This paper tests that relationship on panel data for twenty-three OECD countries over the period 1970-2000, taking advantage of several changes in electoral systems during that period (France, Italy, Japan, New Zealand).  The finding that majoritarian electoral systems lead to lower real prices proves to be remarkably resilient, surviving demanding robustness tests.  The short-run effect of switching to an SMD from a PR system in a given country is a reduction in real prices of about 2 per cent; the long-run effect of having an SMD electoral system, in the average OECD country, is a reduction of at least 10 per cent.