The Regional State Archives in Oslo is responsible for receiving and making accessible to the public archival materials from local and regional government administration within its geographical district. Moreover, the Regional State Archives in Oslo supervises the archival conditions in all local public administration bodies in the region.

The Regional State Archives in Oslo also works to preserve private archives that are worthy of preservation. Thus, the archive acts both as an administrative body and as a science-based cultural heritage institution. The holdings of the Regional State Archives in Oslo fill some 19,000 shelf meters of repository space.