The pedestal of Agrippa stands west of the Propylaia, directly opposite the north wing and the so-called Pinakothiki, and is the same height as the temple of Athena Nike to the south. Originally it was built in honour of Eumenes II of Pergamon in 178 BC to commemorate his victory in the chariot race of the Panathenaic games. Atop the pedestal was a bronze quadriga (four-horse chariot) driven by Eumenes and his brother, Attalos. This chariot was replaced by another in approximately 27 BC, dedicated by the city of Athens to Marcus Agrippa, son-in-law of Augustus, in gratitude for the odeion that he erected in the Agora. The following inscription is still visible on the west side of the pedestal: ?The city (dedicates this) to Marcus Agrippa, son of Leukios, three times consul and benefactor?. Below this inscription are the traces of an earlier one, which probably referred to Eumenes and was erased.
The rectangular, slightly tapering pedestal is the only part of the monument preserved to this day. Made of grey-blue Hymetus marble, it uses pseudo-isodomic masonry, which was particularly popular in the Hellenistic period, and stands on a stepped base of stone and tufa, 3.80 metres long, 3.31 metres wide and 4.50 metres tall. The pedestal is 8.91 metres tall. Its shape resembles that of other Hellenistic pedestals dedicated at large sanctuaries, such as Delphi.