This thesis assesses the participation of the medical profession in the development of the structure of the health system in Mexico between 1917-1988. The thesis considers that the major variable that influenced the development of the health system was the participation of the State as its most important financer, provider and regulator. The shaping of the health system in turn determined the mode of participation of doctors. The period is divided in three subperiods: 1917-1943; 1944-1970 and 1971-1988. The first describes the efforts of the profession to gain control over the demand for health services which remained private after the end of the 1917 Revolution. The second describes the way in which the State intervened in the redefinition of the health system, the achievement of the legal control of professions and the way in which medical work began to be determined by the constraints of institutions despite doctors' efforts to defend their autonomous status. Finally, the third period is characterised by a crisis of the economic and political system with repercussions in the definition of the educational and health policy, and the way doctors were faced these conditions. The thesis also points out the major changes during the period in four of the most important characteristics of the medical profession: professional organization, education, employment and geographical distribution. An analysis is finally presented where theoretical elements are used to interpret the historical events that characterized the participation of the Mexican medical profession in the development of the health system.