This is an early report of application of neutron activation analysis to determine metal composition of Greek coins. Athenian coins evidence a single ore source and a single metallic standard. Certain coins from Corinth were found to be of Athenian silver, with other sources used as well. Multiple ore sources are also indicated for Croton and Caulonia, although a single metallic standard is indicated. Macedon and Syracuse appear to have had a single source of ore, but to have used varying metallic standards. Thasos may have used several sources along with varying metallic standards. Variation in gold content is the best guide to source, while variation in copper content is the best guide to variation in metallic standard.