The archive of the Romano-Germanic Commission contains files, correspondence with domestic and foreign scholars and documents relating to the research of the RGK from its more than one hundred year history. In addition, the RGK is responsible for the central archiving of several external collections. These include the archives of the Reichs-Limeskommission, a sub-collection of the Central Institute for Ancient History and Archaeology of the Academy of Sciences of the German Democratic Republic and the successively growing holdings of the Verbandes der Landesarchäologen in der Bundesrepublik Deutschland e. V. (Association of State Archaeologists in the Federal Republic of Germany). and the West- und Süddeutschen Verbandes für Altertumskunde e.V. In addition, the archive of the Romano-Germanic Commission preserves a wide range of documents relating to the history of the institute as well as the estates of scholars whose work shaped the main research areas of the Romano-Germanic Commission. These include, for example, archival records from and about the former directors of the Romano-Germanic Commission Prof. Dr. Hans Dragendorff (1870–1941), Prof. Dr. Ernst Sprockhoff (1892–1967) and Prof. Dr. Gerhard Bersu (1889–1964) as well as former Commission member Prof. Dr. Georg Kossack (1923–2004). The spectrum of archive materials ranges from letters, diaries, travel journals, notebooks and sketchbooks to manuscripts, reports, files, newspaper articles, plans, maps, documents, photos, films, glass plate negatives, drawings and watercolors.

The extensive material base makes the RGK archive an important source for the history of research and knowledge in archaeology at the end of the 19th and 20th centuries, which is also being researched as part of DAI-Clusters 5 „Geschichte der Archäologie“. Among other things, the archives provide an insight into the creation and development of research projects, the introduction of new methods and techniques as well as unpublished research data, but also into the actors of archaeological research, such as those being researched in the AktArcha project cooperating with the RGK.

The archival records of the Romano-Germanic Commission are continuously indexed in the archive portal iDAI.archives. In addition, since 2021 the Romano-Germanic Commission has been cataloging its archival records together with the Leibniz Centre for Archaeology (formerly the Romano-Germanic Central Museum) via the DFG-funded project “Spuren archäologischer Wissensgenerierung“ in Propylaeum-VITAE.