This paper examines the benefits of regularly playing chess for the intellectual and social-emotional enrichment of a group of 170 schoolchildren from 6-16 years old. It is based on a quasi-experimental design, where the independent variable was the extracurricular activity of chess (n = 170) versus extracurricular activities of soccer or basketball (n = 60). The dependent variable was intellectual and socio-affective competence, which was measured by an IQ test (WISC-R), a self-report test (TAMAI) and a hetero-report questionnaire (teacher-tutor's criterion) applied at the beginning and the end of the academic year. In contrast to the comparison group, it was found that chess improves cognitive abilities, coping and problem-solving capacity, and even socioaffective development of children and adolescents who practice it. The results are modulated, particularly in the area socioaffective, by the personal profile of students who choose practice this activity.