Measles is an illness of universal distribution and great social impact. According to the WHO, the annual deaths due to this disease amount to more than a million children in the world. The objectives of this paper are to estimate the seroprevalence of titer of antibodies to measles in the population of 12 to 59 months of age in Mexico and identify the determinants of the immunity state. From the National Seroepidemiology Survey, 5,232 blood samples of children between 12 and 59 months of age, were analyzed, their blood samples were considered positive when the antibody titers were greater or equal to 1:4, tested by hemagglutination inhibition using sensitized erythrocytes. The National seroprevalence was 76.2 per cent. By age group, an increment in positive level was observed age increased. The seroprevalence was 56 per cent in children of 12 to 24 month and 82 per cent for children 48 to 59 month of age. The history of vaccination was obtained verbally; 62.5 per cent of seropositive didn't have vaccination history and 82.5 per cent were of those vaccinated were positive. By place of residence, at rural level (populations less than 2,500 inhabitants) 74 per cent positives, compared to 79 per cent in children of urban areas. All risk factor were significant, based on a univariate analysis, being the one with greatest risk those with negative vaccine history and children of one year of age. The efficiency of the vaccine estimation was of 63.6 per cent. Risk factors related to the vinculation of immunity protection to measles or seropositives were age, and verbal history of vaccination.