To address the educational gap, many Latin American countries are focusing on extension of the school day and enrichment of the curriculum. In Brazil, a nationwide policy -- Mais Educação -- was implemented in 2008 with this objective. This paper explores the nationwide rollout of the program across the country and compares the performance of schools before and after implementation of the program. The paper quantifies the impacts of the program on student learning and dropout rates in urban areas, and investigates the heterogeneity of impacts by several characteristics of the program's implementation. Participating schools are compared with nonparticipating schools after controlling for school selection into the program based on observable characteristics using propensity score matching. The analysis finds that participation in Mais Educação has on average no impacts on school dropout rates and average negative impacts on mathematics test scores. The negative impacts on student achievement are stronger in the short term, which suggests that the negative effects may be reduced as the program improves its implementation. In addition, especially for fifth-grade schools, the level of student spending is associated with reduced dropout rates. Interestingly, in schools choosing the fields of Portuguese and/or sports in the added hours, the program is associated with lower test scores in Portuguese and mathematics. Finally, for the sample of fifth-grade schools, heterogeneous impacts are seen in the program according to the GDP per capita of the city where the school is located. The higher the GDP per capita, the greater the positive impact of the program on mathematics test scores and on dropout rates.