Inside the neoclassic Palazzo Parpaglia, the museum houses several archaeological collections from the excavations of Tharros, a picture gallery and a section dedicated to the city during the period of the Giudicati.
The art gallery of San Martino (XV century) attributed to the school of the Catalan painter Ramon de Mur is worth mentioning in the picture gallery.
The altarpiece of Christ (1533), the work of the school of Peter Cavaro have been preserved only nine boards.
The altarpiece of the Madonna of the Directors (1565), the work of Cagliari Antiochus Mainas represents the councilors of the city of Oristano kneeling around the Madonna.
Of the rich archaeological collection it is to be noted the more than two thousand obsidian scrapers in the Neolithic period, the clips in the bone, amphoras from Greece and Etruria, glass and Roman oil lamps.
All the exhibits are part of the Collection Ephisius Pischedda which are flanked by smaller collections (Pau, Paper, Sanna-Delogu).
Among the most important pieces of a mask made of terracotta, green jasper scarabs and jewelery with engravings of Roman times.