This work explores the political economy of competition policy in Mexico in order to answer the question of how Mexico''s political institutions influenced both the aims of microeconomic reform and the ability of the government to implement it. The evidence is reviewed in the context of the economic approach on the politics of regulation and the politics of anti-monopoly policy. Following an institutional perspective, this research addresses how and why the Mexican government implemented the competition policy reform, and analyses the institutional design of the competition regime and overall decision-making process. This work argues that the key generator for reform is not found in the maximization of consumer welfare but in pragmatic and ideological concerns related to the credibility of economic reform. The research shows that the competition policy in Mexico responded not only to economic motives but also political and ideological considerations. By studying the politics of competition policy, this work provides insights into the current issue of the consolidation of Mexico''s economic reform.