Introduction: Anemia is a common finding in most developing countries. Of all populations, children are the ones who suffer most from anemia due to the long-term effects it can have on their growth and development. Large scale public programs to prevent anemia should always be based on epidemiological studies from significant sample sizes. Patients and Methods: We included elementary school children from the state of Nuevo León, in northern Mexico (pop 4.2 million). We selected the children from eight public schools, six from Monterrey’s metropolitan area (pop 3.5 million) and two from the suburban area (pop. 0.5 million), mimicking the population distribution in our state. Three of these elementary schools give out school lunches consisting of milk and peanuts. Hemoglobin levels were obtained by using a Beckman-Coulter HMX® automated system (Miami, FL). We defined anemia as less than 12 g/dL of hemoglobin. Results: After obtaining informed consent from the parents, we studied 1,137 children (550 males, 587 females), all of them between 6 and 12 years of age. Mean hemoglobin was 13.18 g/dL for females and 13.27 g/dL for males. We found 53 cases of anemia: 21 males and 32 females. Among the 53 anemic patients, 50 had hemoglobin between 11–12 g/dL, 1 between 10–11g/dL and 2 between 9–10 g/dL. We found significant differences in mean leukocyte numbers (7,200 vs 6,500/uL P=0.018); Mean Corpuscular Volume (82.9 vs 82.10 fL P=0.39); Mean Corpuscular Hemoglobin (29 vs 28.6 ug P=0.001), between the non-anemic and the anemic patients. Comparing the number of anemic children between schools with (28.7%) and without (71.3%) school lunches, the proportion of anemic children was significantly increased (26 vs 27 P=0.001) in schools that do not provide this school lunch. Conclusions: Our results show a very accurate picture of the status of anemia in the urban and suburban areas of the state of Nuevo Leon in northeastern Mexico. Although one anemic child is one to many, our results show marked improvement when compared with our national means. Even though there are other factors that influence the absence of anemia in the different schools, the administration of the school lunch appears to have beneficial effects on anemia in our population.