This research aimed to explore Léon Walther's travels through Brazil in 1929, as well as verify how the ideas of techno-psychology were initially implemented at the Escola Industrial de Natal (EIN). Newspapers from the cities of São Paulo and Rio de Janeiro where he passed through, and from the city of Natal, where EIN is located, were analyzed, as well as ordinances from 1956 and 1957 that deal with the selection processes for admitting students to the institution. and Walther's book (1929). The sources were analyzed based on Le Goff's (1954) document-monument concept. It was possible to identify that the ideas of techno-psychology were implemented in the institution, initially, in the student admission process, with the inclusion of the mental aptitude criterion using psychological tests.