A method and system supporting handoff of a multimedia call session using background network scanning is disclosed. A mobile multimedia handset may engage in the exchange of a multimedia information stream via a first wireless network, and may sniff a portion of radio frequency spectrum for a second wireless network. Information about available services and network quality of service for the second network may be received by querying the second wireless network or from advertising by the second wireless network. Hand-off between the two networks may be based upon the results of the comparison and one or more user-defined criteria, and the handoff may be synchronized according to predefined events in the stream of multimedia information.