A method of providing a handover service to a mobile communication terminal supporting multi-modal communications, and a mobile communication terminal for performing the method are provided. More particularly, a method of eliminating an interruption of a data transmission service occurring during a handover between different communication networks, and a terminal for performing the method are provided. A method of providing a handover service of a mobile communication terminal supporting multi-modal communications can include: transmitting and receiving data to/from a corresponding node via a first access network and a second access network while simultaneously maintaining an association with the first access network and the second access network, determining a point in time of completing a handover registration, and releasing an association with the first access network after the point in time of completing the handover registration.