The Ages and Stages Questionnaire Third Edition in translation to Portuguese-BR (ASQ3-BR) is a screening test used to evaluate the development of children in pre-school age (8-60 months) in five areas of development: Communication Coordination Wide motor, coordination motor Fine, Troubleshooting and Personal and Social and applied by the Secretariat of the Rio de Janeiro Education 124,292 children in 468 public kindergartens in the city of Rio de Janeiro, in the years 2010, 2011 and 2012. A statistical analysis of the scores was carry on of each child in order to identify the normative interpretation through the means and standard deviations as well as 5 percent and 10 percent percentiles. These results were compared with normative values of American original instrument, to confirm its psychometric properties and identify differences between results. In a second approach, the scores were assessed on their internal consistency using the coefficients of Cronbach s Alpha and Correlation Item-Total to identify possible instrument s discrepancies with the reflection in its reliability when applied in day care environment. The results showed that although the ASQ3-BR is a good instrument with same psychometric properties of the original English version, is likely to have increased their reliability when applied in day care environment by adapting some items that can take into account the day care specific operational procedures.