The Temple of the Genius Augusti was built upon the requests of Mamia, mentioned in an inscription as priestess of Cerere and of the Genius of Augustus. The construction of this temple in the Augustan period (first decade of the 1st century AD) adopted the same architectural design as the adjacent Portico of Concordia Augusta, as indicated by the marble decoration of the façade, the bottom part of which can now only be seen, by motives in a niche and the renewed altar and partly completed after the earthquake of 62 AD. The temple included a small courtyard, an altar and a small temple with four columns on a high basis, accessible from both sides.

The beautiful marble decoration with floral motives filled with rich fauna, today seen at the entrance of the Portico of the Concordia of Eumachia, was likely to belong to the entrance of the temple. The frieze was made based on the model of the Ara Pacis in Rome.

Date of excavation: 1817.