Fairness in finance is an intrinsic and challenging goal of health systems. Mexico recently devised a structural reform that responds to this challenge. Through a new system of social protection in health that will offer public insurance to all citizens, the reform is expected to reduce catastrophic and out-of-pocket spending while promoting efficiency, more equitable resource distribution, and better-quality care. This paper analyzes the reform, focusing on financial features, expected benefits, and future challenges. It also highlights aspects of relevance for other countries that are striving to formulate and implement health policies to promote universal social protection and fair financing.