OBJECTIVES: Estimate potential direct savings for the Mexican Healthcare System generated by the operation of the "Technical Guidelines for the Sale or Distribution of Food and Beverages in Establishments of Basic Education" METHODS: The micro-simulation model "Chronic Disease Prevention (CDP)" developed by OECD-WHO was used for projecting health gains and costs of treatment in a period of 100 years. The model was adjusted to accommodate the range 6-14 years old stated in the Guidelines. Mexican data on incidence, prevalence, mortality, population at risk, annual unit costs and relative risk of selected chronic diseases (diabetes mellitus type 2, hypertension, cardiovascular, hypercholesterolemia) attributable to obesity and the treatment of obesity as disease itself was used. Sensitivity analyses were developed for most variables used in the model. RESULTS: Under a base case scenario present value of potential savings in total spending on medical care associated with the implementation of the Guidelines amount to USD$1,052.2 million in 2008. Most savings are derived from averted cases of hypertension (32.7%), obesity-overweight (28.6%) and diabetes mellitus type II (17.8%). Results are robust to changes in all parameters analyzed. Amounts obtained are an underestimation of potential savings as neither expensive complications as renal failure nor other chronic diseases attributable to obesity as arthritis, colorectal or breast cancer were included. CONCLUSIONS: The Guidelines, —developed by the Ministry of Public Education in coordination with the Ministry of Health—, represent a good example of cooperation among different sectors to solve a complex public health problem. Results shows the importance of implementing preventive interventions aimed at reducing the prevalence of chronic diseases related to poor eating habits, inadequate physical activity and obesity in Mexico. Implementation of the Guidelines involves significant direct savings that can be assigned to other health needs of the Mexican population.