One of the most important issues related to the development of a city is its water sources and their conveyance to the city. The ancient writers Libanius and Malalas praised the water supplies of Antioch, the beauty of its sources and the advantages they provided to the city. According to Ioannes Chrysostom (4th century A.D.), Antioch had a population of 200,000 people at the end of the 1st century based on information from its bishop Ignatius. Haddad states in his article entitled "The Population of Antioch," using information provided by Libanius and Ioannes Chrysostom, that in the 4th century A.D. Antioch's population reached 250,000 people. This number should be considered half a million with slaves included. The high population and water demand of the city are at a comparable level to those of Rome, and this must have required a developed system of water supplies. The water supplies are among the most impressive remains of the ancient city. Travelogues mention at least three water supply bridges as well as cut channels and cistern remains. Excavations conducted in Antakya between 1932 and 1939 also covered the water supplies, but no extensive survey was done.For the first time in 2002 extensive surveys of the water supplies were initiated and their remains documented. In addition to the identification of the water supplies, the sources and all the elements constituting the water conveyance system of the city were studied. According to ancient sources, water supply construction started in the reigns of Seleucus I and Antiochus III, soon after the city's foundation, and water was brought to the city from Daphne (Harbiye). Our surveys have shown that, apart from the sources at Daphne, other main sources supplying water to Antioch were at Zugaybe and Kuruyer, which has dried up to a great degree today. In addition to these fault line-karstic sources, precipitation was the other important factor in supplying the city. The region's average annual precipitation is 1097.8 mm. Therefore wells utilizing underground water and cisterns collecting the precipitation were initially effective parts of the water supply system. Yet it is certain that the wells and cisterns fell short of supplying adequate water as the city came under Roman rule and grew rapidly.At this time water supplies utilizing sources in the surrounding area gained in importance. According to our surveys, during this period Antioch was supplied with water via four water supplies: the double-channel of Harbiye and single channels of Dursunlu and Kuruyer. These water supplies were comprised of masonry channels, cut channels, water collection tunnels, bridges, terra cotta conduits as well as eight bridges. The water supplies of Antioch developed immensely, especially in the first and second centuries A.D.and stayed in use for a very long time period. They were repaired or rebuilt until the end of the 6th century A.D. when the development of the city slowed down. In spite of this advanced network of water supplies, the water supply system did not depend on a single source or structural type. In fact, wells and cistern continued to be used. As a result, the water supply of Antioch reflects a system that comprised a variety of structural types and techniques developing and diversifying in parallel to the growth of the city and integrating monumental structures.