It differs from the theatre in function, being used for meetings of the municipal council and concerts. It also differed from the theatre in being roofed by a wooden awning providing protection from sun and rain. It had seating for between 1500 and 2000. The first five tiers above the orchestra are original, with the stairs adorned with lion's paws in a very good state of preservation. An extraordinarily beautiful head of Eros found in the orchestra area is now exhibited in the Selcuk Museum.
 

The Odeum is one of two open-air theaters in Ephesus. The main theatre, which was colossal and could seat 20,000, and the smaller Odeum. Unlike its larger counterpart, was used for civic meetings in addition to the dramatic performances. It is in an astonishingly good condition, especially since it dates from 150AD. It had a stage and an orchestra and a marbled podium.

J.T. Wood, who was working on excavations at Ephesus for the British Museum between 1863 and 1874, excavated the odeum and theatre. In 1869 he struck a corner of the Artemiseum, and later his excavation exposed not only the scanty remains of what we new see, but the platform below it of an earlier temple of identical size and plan subsequently found to be that of the 6th century BC, to which Croesus contributed. The sculptured fragments of both temples were sent to the British Museum. In 1904 D.G. Hogarth, heading another mission from the museum, examined the earlier platform and found beneath its centre the remains of three yet older structures. These date from c. 600 BC.