The Central Reserve Bank of Peru (BCRP) has been targeting inflation for more than a decade, using Lima’s inflation as the operational measure. An alternative indicator is countrywide inflation, whose quality and real-time availability have improved substantially. Given these competing measures, two policy questions arise What have been the implications for national inflation of targeting Lima’s inflation? Would shifting to a national aggregate significantly affect the workings of monetary policy in Peru? To answer these questions, we estimate a large, but parsimonious, error correction model and investigate how regional shocks propagate across the country. The results indicate that a shock to Lima’s inflation is transmitted fast and strongly elsewhere in the country, whereas the effects of shocks in other regions are limited and short-lived. This constitutes supporting evidence to the view that by targeting Lima’s inflation, the BCRP has effectively, albeit indirectly, targeted national inflation.