[Coverage of health services]

In this paper the concepts and criteria related to health coverage are discussed in the context of the organization of national health systems. The main international agreements based on WHO/PAHO proposals are also described. The relationship between primary health care and health coverage is analyzed and the evolution of the programs for the extension of health coverage in Mexico are discussed, with emphasis on the problems of overlap and definition of the universe in the several institutions of the health sector. Finally, the author reviews the problems to measure coverage in order to guarantee social and operative efficiency of the Mexican health system.