To describe Chile's stage of epidemiological transition, a descriptive study of the changes to the demographic and economic profile of this country during the last 20 years is presented. The decline in the total fertility rate from 3.4 in 1970 to 2.6 in 1992 and the important decrease in general and infant mortality rate has led to an increase of life expectancy of 8 years for men and 9 years for women. This has resulted in changes to the age structure and causes of mortality and morbidity of the population. A reduction of 82% in the proportion of deaths among children <1 year and a 73% increase of mortality amongst those 65 years and older can be observed. In line with these changes non-communicable diseases have increased from 53.7% of all deaths in 1970 to 74.9% in 1991. In the same period mortality rates from cardiovascular causes have decreased from 189.6 to 161.1 per 100 000 population, whilst their relative proportion of all causes has increased from 22.3% to 29%. High prevalence of risk factors should lead to a significant increase of chronic diseases in future years. Regarding morbidity, a high incidence rate for tuberculosis persists together with an increase of infections of the digestive system and of sexually transmitted diseases. A decrease in the rates of diseases preventable by immunisation has been noted. It is concluded that, as defined by population mortality statistics, Chile is in a post-transition stage but with a persistence of some infectious diseases corresponding to a transitional stage of development.