The history of Brazilian theatre goes back as far as five hundred years and yet to this day arises the issue of where and how is preserved the memory of such an artistic heritage that is very representative of Brazilian culture. The aim of this paper is to analyze the preservation process of onstage costumes of Palácio das Artes, one of the most important theatres in the Brazilian State of Minas Gerais, building upon reference documents, interviews and technical visits undertaken in 2014. A technical analysis of the process and a flowchart are used to encourage the implementation of projects related to management improvement, conservation tools and collection storage adequacy – both functional and museological –, as well as to the development of preservation policies. It is also expected that this study might stimulate the continuation of such practices in this theatre and their adoption by other institutions.