According to Nelson's (1976) criteria, the MCST (MWCST) is a simplification of the Wisconsin Card Sorting Test (WCST). As the MCST is particularly suitable for children, the aim of this study was to establish the normative data presently lacking for that group. The MCST was administered to 1126 normal children aged 4 to 13 years. Scoring was based on all the classical parameters, according to existing criteria, plus two new ones that we propose (“categorizing efficiency” and “categorizing efficiency plus”). Strong correlation (or inverse correlation) with age is found for most parameters, including all criteria used for perseverative responses. This does not occur for “failure to maintain set,” calculated according to the usual criteria. “Categorizing efficiency” and “categorizing efficiency plus” avoid the ceiling effect occurring at higher ages in the parameter categories. The MCST may be used in children 4 years of age and above. Most, but not all, of its parameters show regular improvement with age, demonstrating their validity. However, our data suggest that a participant's performance on the MCST may be based essentially on two parameters: categorizing efficiency (or categorizing efficiency plus), measuring the participant's ability to categorize, and perseverative errors (or percent perseverative errors), measuring his or her difficulty in shifting, both considered typical executive functions.