This large structure, situated at the south-west corner of the Altis, was built over the Classical sanctuary of Hestia and other buildings demolished for this purpose. A lead water-pipe inscribed NER. AVG. and other indications, support the identification of the building as the House of Nero, built in AD 65-67 for the emperor's visit to the Olympic Games of AD 67, in which he participated. The building was remodeled and enlarged several times until the fourth century AD.

This opulent residence comprised a spacious peristyle court surrounded by many rooms and gardens. The entrance on the west side was preceded by an arched portico and opened onto an atrium from which two corridors lead to the court. The south wing housed the baths. The building was altered in later years by the construction of the so-called east baths which date to the reign of Septimius Severus (early third century AD). This large new structure kept the west fa?ade, the central court and several rooms of the House of Nero. It also contained several frigidaria (cold rooms) and caldaria (hot rooms), pools and gardens. The well-preserved tepidarium (tepid room) in the south-east corner was a huge octagonal room built of bricks, with vaulted ceiling and a remarkable mosaic floor depicting marine life. West of the building are the foundations of Nero's triumphal arch and the remains of a small odeion of the third century AD.

The monument - in particular the surviving wall-plaster, was recently restored and has been open to the public since 2002.