Abstract: An adaptive file delivery system and method transmits a data file, such as an audio-video file, over a network or collection of networks in segments, each segment transmitted during a different time period. In one embodiment, data files are transmitted on behalf of a third party using one or more service provider networks. In an exemplary embodiment, the third party contracts with the sending system to transmit the data files using the service provider networks to transmit data files to customers of the respective service provider networks. The data file is transmitted as a plurality of segments and transmitted in such a way so as to prevent congestion in the respective service provider networks.