This paper aims to present and contextualize a selected set of documents from Gleb Wataghin’s archive at the Historical Archive of the University of Turin, useful for studying his participation in the Brazilian-Italian scientific cooperation in the 20th century. Wataghin was a Russian-Italian physicist who graduated from the University of Turin, where he also became a professor. In the 1930s, he was invited to contribute to the organization of the Department of Physics of the Faculty of Philosophy, Sciences, and Letters of the University of São Paulo, in Brazil. As observed in the documents from this archive, Wataghin’s Brazilian experience was fundamental for the building of Brazilian-Italian cooperation in physics, in times of positive diplomatic relations between the two countries. Beyond that, these documents are also relevant to study other aspects of Wataghin’s life, as well as his networks of cooperation with other countries.