To analyze secular trends of coronary heart disease morbidity and mortality in Mexicans protected by the Mexican Institute of Social Security. An ecological trend analysis study was conducted on coronary heart disease morbidity and mortality in the Mexican population protected by the Institute. All deaths were adjusted for miscoding and misclasification and rates were age - adjusted according to the age distribution proposed by the World Health Organization. Hospital discharges, as well as the number of patients seeking medical care for coronary heart disease, were analyzed as an indirect incidence measure. Fatality rates and the mean number of hospitalization days were also estimated. Coronary heart disease mortality has shown a stable trend at the end of last century and a descending trend in the in the first year of this century, both in males (r=0.84;r2=0.70; p