This presentation will examine the origins of an important health policy of the second half of the 20th century: Primary Health Care and its role and impact in some Latin American countries. This policy was considered as an alternative to traditional "vertical" disease-oriented programs that emphasized technology and paid little attention to community participation. Cueto will also analyze the role played by the Pan American Health Organization, the World Health Organization and UNICEF in the emergence and diffusion of the concept of Primary Health Care during the late 1970s and early 1980s. Special attention will be given to the political context in which PHC emerged, the methodologies and technologies associated with the primary health care perspective, and the debates on the meaning of primary health care.