This thesis consists on two independent parts. The first one is an empirical evaluation of political budget cycles in Brazil. The research question is twofold. We ask the factual question of whether municipal level receipts and expenditures vary with the proximity of elections for mayor. Then, we investigate the effects of political competitiveness and govern transparency on the size of the budget cycles. Our results suggest the existence of strong budgetary cycles in the Brazilian municipalities, though it is difficult to identify a causal relationship between such cycles and the electoral calendar. Also, according to our findings, higher political competitiveness and lower govern transparency generate incentives for the incumbent mayors to invest more in the last year of their terms. In the second part of the thesis, we estimate the impact of political advertising on candidate performance in Brazilian mayoral and gubernatorial elections. Previous studies have established a minimal effects conventional wisdom that campaign spending and advertising have little impact on elections outcome. However, such studies suffer from omitted variable bias and reverse causality. We explore a quasi-natural experiment produced by Brazilian electoral legislation, and show that TV and radio advertising have a strong effect on candidates´ electoral performance.