Political theorists and enthusiasts of basic income advocate that an unconditional, periodic, and nonwithdrawable cash payment can encourage voter turnout by freeing up time, energy, and the cognitive bandwidth of citizens. This paper provides the first quantitative assessment of this argument by studying Renda Básica de Cidadania (RBC) - currently the largest basic income program in Latin America. Since 2013 RBC has paid a monthly transfer equivalent to 15% of the Brazilian minimum wage to 42,000 (25%) of the individuals living in Maricá, located in Rio de Janeiro. Estimates from a difference-in-differences design show a substantive and statistically significant increase in voter turnout in Maricá. In addition, RBC reduced the share of votes typically caused by voters' lack of knowledge about candidates (blank votes) or dissatisfaction with the quality of candidates running for office (null votes). These effects appear in local and general elections and are robust across different models.