To determine the treatment needs and the care index for dental caries in the primary dentition and permanent dentition of schoolchildren and to quantify the cost of care that would represent the treatment of dental caries in Mexico.A secondary analysis of data from the First National Caries Survey was conducted, which was a cross-sectional study conducted in the 32 states of Mexico. Based on dmft (average number of decayed, extracted, and filled teeth in the primary dentition) and DMFT (average number of decayed, extracted, and filled teeth in permanent dentition) information, a treatment needs index (TNI) and a caries care index (CI) were calculated.At age 6, the TNI for the primary dentition ranged from 81.7% to 99.5% and the CI ranged from 0.5% to 17.6%. In the permanent dentition, the TNI ranged from 58.8% to 100%, and the CI ranged from 0.0% to 41.2%. At age 12, the TNI ranged from 55.4% to 93.4%, and the CI ranged from 6.5% to 43.4%. At age 15, the TNI ranged from 50.4% to 98.4%, and the CI ranged from 1.4% to 48.3%. The total cost of treatment at 6 years of age was estimated to range from a purchasing power parity (PPP) of USD $49.1 to 287.7 million in the primary dentition, and from a PPP of USD $3.7 to 24 million in the permanent dentition. For the treatment of the permanent dentition of 12-year-olds, the PPP ranged from USD $13.3 to 85.4 million. The estimated cost of treatment of the permanent dentition of the 15-year-olds ranged from a PPP of USD $10.9 to 70.3 million. The total estimated cost of caries treatment ranged from a PPP of USD $77.1 to 499.6 million, depending on the type of treatment and provider (public or private).High percentages of TNI for dental caries and low CI values were observed. The estimated costs associated with the treatment for caries have an impact because they represent a considerable percentage of the total health expenditure in Mexico.