OBJECTIVE This work aimed to determine the migration patterns of medical students within Mexico. METHODS We obtained the places of origin of graduates and the states where they registered their medical degrees at the Ministry of Education General Registry of Professions (SEP), between 1970-1974, 1980-1984 and 1985-1989. Data were organized as follows: Attracting foci, sending foci, transition foci, and important migrant flows. RESULTS The concentration of medical human resource development, is reflected by the existence of a few attracting foci (D.F., Jalisco, Nuevo Leon, and to a less extent, Puebla and Michoacan). Also, we observed the persistence of traditional sending foci (Guanajuato, Chiapas, Colima, Campeche). However, some important changes occurred throughout the study period, namely, a decrease of the migratory mobility of university students. During 1970-1974, almost half of them (47%) obtained their degrees outside their place of origin; during 1980-1984 this figure decreased to 34% and during 1985-1989, it decreased further to 30.6%. Second, the participation of D.F. as a main human resource development center diminished; from 59% to 40% during 1970-1974, it went down, to 30% in the following quinquennium, while it increased in Jalisco, Michoacan and Nuevo Leon. CONCLUSIONS The establishment of medical schools in almost every Mexican state has had a central role in the migration patterns of medical students. Nevertheless, our results show that there are other reasons accounting for the persistence of the concentration of medical human resources development in main cities of the nation such as Guadalajara and Monterrey.