Earlier work has tended to view Delos as an entrepôt for the larger Hellenistic grain trade, but during the years of independence the island relied on the import of grain to satisfy local demand, and this was certainly the more important aspect of the trade in grain, at least from the Delians' point of view. This study explores several issues connected with the local supply of grain. From prices for grain reported in inscriptions and estimates of the local population, the (...) aggregate annual demand for grain is estimated, and the price structure of grain derived; the ratio of wheat and barley prices on Delos is found to differ considerably from that known from Athens and Roman Egypt. The shortage of 282 B.C., assumed by earlier scholars from prices recorded for that year, is shown instead to be a period of atypically low prices. The impact of the sailing season on shipments of grain is explored, and an annual rhythm in grain prices and availability linked to the closure of the sea and the agricultural year is revealed. The Delians tried to reduce the impact of these fluctuations by the public purchase of grain on an irregular basis in the late fourth and third century, as attested through public loans; by the last quarter of the third century they had established a regular sitōnia fund to buy grain for resale at reduced prices. Comparison of funds available, grain prices, and the estimated aggregate demand suggest that the Delian sitōnia was able to cover a significant fraction of local demand; this contrasts with evidence from other cities. Some of the implications of these results for our understanding of the Hellenistic economy are briefly explored. (shrink)