The Odeon or theatrum tectum as it was called by the Romans, was built during the early years of the colony (79 BC), as evidenced by an inscription, as requested by two local magistrates, Marcus Porcius and Caius Quinctius Valgus who also requested the construction of the amphitheatre. This building was dedicated to the representation of the most popular theatrical genre at the time, miming, and could also be used for musical and singing performances.

It was richly decorated with multi- coloured marbles whereas large male tuff figures (telamones) supported the steps. The structure was completely covered by a functional roof to improve the acoustics. The plaster of the external masonry retains many graffiti of the spectators of the shows that were held here, sometimes even from very distant regions.

Date of excavation: 1769; 1792-1795.