A catalogue of the sculpture discovered during excavations by the University of California at Los Angeles in the sanctuary of Poseidon at Isthmia. The sculpture ranges in date from ca. 100 B.C. to ca. A.D. 400, with most of the 107 pieces included belonging to the mid-2nd century. Many of the fragments were found in the ruins of an elegant public bath building and may represent remnants of its decoration. The sculpture illustrates the artistic taste of the Antonine period and provides a glimpse of the interior decorative program of a major public building located in a Panhellenic sanctuary. Individually, the sculptures, which range in scale from miniature to colossal, raise intriguing questions about style, iconography, and religion. Important pieces published in this volume include two portrait heads of Polydeukion and a relief stele with twin Cybeles. Since most of the discussion is provisional, the author hopes that this preliminary publication will encourage other scholars to explore, debate, and eventually resolve the issues raised.