After surveying the Child Education Municipal Centers (CEMEIS) and private day care centers of a medium-sized city in the State of São Paulo, it was found a population of 570 children aged 2 years, 470 (83%) attending the municipal network and 100 (17%) the private schools. These children are distributed in 40 day care centers: 22 (55%) in municipal institutions and 18 (45%) in private day care centers. After sample size calculation for finite populations, with two-tailed alpha of 5% and 95% confidence interval, a sample of 80 children was estimated. This calculation does not require the definition of an outcome.