The article is devoted to the study of the activities of pedologists of the Chuvash ASSR and aims to analyze the historically first study devoted to the intelligence of Chuvash children. The study is based on the publications of the first pedologists from Chuvashia F. P. Petrov and M. E. Efimov. In accordance with the historical and psychological methods described by V. A. Koltsova, the work uses problematic and source study methods. The study is written in the aspect of the history of pedagogy. A graduate student of the Kazan Oriental Pedagogical Institute, F. P. Petrov with a team of students, for the first time carried out a comprehensive study of the intellectual development of Chuvash children using the Binet-Simon test method, widely known among Soviet pedologists. At first, pedologists took the test method in Russian, then it was translated into the Chuvash language with appropriate text changes in relation to the everyday and speech characteristics of the Chuvash. The result of the study was the book published in Cheboksary, "The experience of studying the intellectual development of Chuvash children using the Binet-Simon method", published in 1928. The book caused serious objections from the head of the pedological office at the Chuvash Scientific Research Institute M. E. Efimov; he believed that the author was biased against Chuvash children and violated the methodological principle of making tests. The correspondence polemic between two Chuvash pedologists about the measurement of children’s intelligence, along with similar cases in the country’s republics, prompted L. S. Vygotsky to call for an understanding of the problems of national pedology, with its leading problem – the measurement of intelligence.