To determine the prevalence of tobacco consumption among the active insured population of the Mexican Social Security Institute. A cross-sectional study in which the active insured population from the 36 political delegations was interviewed by means of a structured and self-applicable questionnaire on tobacco consumption, age of initiation, amount of cigarettes consumed and suspension. The sample consisted of 45 117 subjects, of which approximately half were men and half women. Smoking prevalence in men was 40% and in women, 17.6%. Prevalence was highest in the north of the country. There is an effect of age on tobacco consumption and more than half started smoking during adolescence. Smoking prevalence was found to be high, however, the average number of cigarettes is low. Suspension index is low. Public health measures are necessary to diminish this addiction.