The Epigraphic Museum is unique in Greece and the largest of its kind in the world. It safeguards 14,078, mostly Greek, inscriptions, which cover the period from early historical times to the Late Roman period, primarily in Greece.

The museum is housed in the south wing ground floor of the National Archaeological Museum. It comprises an internal and external courtyard (atrium), a lobby, eleven rooms, a large hypostyle Pi-shaped corridor, a gallery, offices, a laboratory for the conservation of inscribed stone monuments and lavatories. Only the courtyards, lobby and four rooms are open to the public; the other premisces are accessible only to researchers and staff.

The purpose of the museum is the scientific research, study, registration, protection, preservation, publication, photographic documentation and promotion of the ancient Greek inscriptions.

The museum also aims to comprise photographic and impression archives and a specialized epigraphic library. Moreover, a digital catalogue of the inscriptions has been constructed.

The Museum organises temporary exhibitions of ancient Greek inscriptions, as well as exhibitions of art inspired by the Greek script and the ancient inscriptions.