The Stadium, which could accomodate 40.000 spectators, was built 400 m SE of the Temple of Zeus.
The track (total length of 178m) was bordered by a stone water-channel with stone basins at intervals for drinking water. The stone starting line was on its western extremity. A rectangular building with an internal colonnade on its western side served probably as a "changing room". From it, the athletes and the judges entered the Stadium through a vaulted tunnel. The spectators sat in roughly levelled terraces (degrees), cut in the soft rock, while two or three rows of seats were constructed between the starting-line and the stoas.
The Stadium in which Panhellenic games were held every two years in honour of Opheltes, was built at the end of the 4th century B.C., as part of a renovation project of the Sanctuary. In about 270 B.C., the games were transferred to Argos. Despite an attempt in 235 B.C., of Aratos of Sicyon to bring them back to Nemea (and indeed, for a while, they took place alternately in Nemea and Argos), the games were definitively transferred to Argos not long after.
The stadium was excavated in 1974-1981 by the American School of Classical Studies (University of Berkeley, California) under the direction of S. Miller.