A study was carried out in 1970 on the distribution of medical personnel in Mexico. At that time an unequal distribution of physicians was detected, but not emphasized given the general shortage of physicians in the country. At the present time, the situation has changed. In this article the analysis of the 1990 census data using traditional indicators of availability of physicians in the country, as well as indirect criteria of physician requirements is presented. In the year of reference there were 157,407 physicians in the country, with a national average of 673 persons per physician. The distribution of physicians by state showed a great deal of variation in the number of persons per physician. For example, the state of Chiapas has 1,642 inhabitants per physician, whereas the Federal District has 292. The relation between trained and employed physicians shows another important phenomenon: there is a high percentage of physicians that do not practice clinical medicine (19.4%). Nevertheless, the number of physicians almost tripled the growth experienced by the general population, and important differences among and within states do persist. Furthermore, a new paradoxical effect has emerged, the presence of underemployment and unemployment of physicians, even in communities with greater needs for medical care. This indicates that the strategy of training more physicians has not solved the problems of accessibility and coverage, but in fact has fostered new problems and perhaps greater inequalities.