This document summarizes Ronald MacLean-Abaroa's presentation on fighting corruption in La Paz, Bolivia. When he took office as mayor in 1985, La Paz was facing a financial crisis due to hyperinflation and lost revenues. Corruption was rampant across the city government. MacLean-Abaroa conducted a participatory diagnosis of corruption issues. He then developed a strategy focusing on institutional reform, using a principal-agent model to improve incentives and accountability. Key reforms included downsizing personnel, simplifying taxes, deregulating permits, and increasing transparency and competition in procurement. These steps helped collapse corruption and significantly increase revenues, investments, and the city's creditworthiness.