Governments around the world have adopted unprecedented policies to deal with COVID-19. This paper zooms in on business shutdowns and investigates their effectiveness in reducing mortality. We leverage highly granular death registry data for almost 5,000 Italian municipalities in a diff-in-diff approach that allows us to mitigate endogeneity concerns credibly. Our results, which are robust to controlling for a host of co-factors, offer strong evidence that business shutdowns are very effective in reducing mortality. We calculate that the death toll from the first wave of COVID-19 in Italy may have been about twice as high in their absence. Our findings also highlight that timeliness is key – by acting one week earlier, the death toll may have been reduced by up to an additional 25%. Finally, shutdowns should be targeted. Closing service activities with a high degree of interpersonal contact saves the most lives. Shutting down production activities – while substantially reducing mobility – only has mild effects on mortality.