This is a preliminary report on the UCLA excavations of 1973 and 1974 at Achilleion, Greece, that were conducted in cooperation with Greek authorities. Achilleion lies in the heart of Thessaly and is a stratified neolithic mound which yielded a cultural sequence supported by radiocarbon dates and stratigraphy from ca. 6500 to 5500 B.C. The excavations have revealed vital information on the environment, economy, architecture, ceramic industry, and religion of the Sesklo civilization.