This presentation focuses on the analysis of letterings found in architectural drawings from a corpus of 170 design plans from seven major architects based in São Paulo, Brazil between 1925 and 1955. It takes into account the letters used to convey information, and also those designed to be part of the buildings. The letters and letterings present in the architectural drawings repeated graphic characteristics found in architectural lettering on art déco buildings from the same time period. We found great diversity in the use of lettering models in the various offices. The design of letters for architectural use sought to understand how it was done and detailed. Additionally, a survey of lettering and calligraphy teaching practices in the main professional courses for architects and draftsmen in São Paulo was conducted.