A well-ordered catalogue of all the terracotta lamps excavated between 1952 and 1967 by the University of Chicago in and around the sanctuary of Poseidon at Isthmia. The most important and complete pieces are presented with short descriptions and illustration while the fragments are merely listed. Most of the finds are from the 1st century A.D. and were imported from Corinth (Corinthian type XVI). Later in the century these imports were replaced by a local product, found in huge quantities around the Temple of Palaimon (1,221 pieces are catalogued). These cult lamps present the major new type from Isthmia as most of the other pieces published are well-known elsewhere. The entire assemblage is grouped into four chronological periods: Classical Greek lamps, mainly used in the Poseidon sanctuary; Hellenistic lamps down to the Mummius destruction of 146 B.C.; Roman lamps dating from 44 B.C. to the 3rd century A.D.; and a miscellaneous group of Late Roman lamps, down to about the 6th century A.D.