Do better-informed people vote more? Recent formal theories of voter turnout emphasize a positive effect of being informed on the propensity to vote, but the possibility of endogenous information acquisition makes estimation of causal effects difficult. I estimate the causal effects of being informed on voter turnout using unique data from a natural experiment Copenhagen referendum on decentralization. Four of fifteen districts carried out a pilot project, exogenously making pilot city district voters more informed about the effects of decentralization. Empirical estimates based on survey data confirm a sizeable and statistically significant causal effect of being informed on the propensity to vote.