The present invention relates to a method and apparatus for transmitting and receiving data using a plurality of carriers in a mobile communication system. The communication method by a terminal according to one embodiment of the present invention includes the steps of: receiving a secondary cell (SCell) adding command including setting information on an SCell to be added from a primary serving cell (PCell); transmitting a preamble to the SCell to be added; receiving a random access response message (RAR) for the SCell to be added; and, if the SCell adding command includes an indicator indicating that a first base station to which the SCell to be added belongs and a base station to which the PCell belongs are different from each other, applying parameters included in the RAR to the SCell that transmits the RAR. According to the embodiment of the present invention, by aggregating carriers between different base stations, a terminal can have increased chances of transmitting and receiving data at high speed through the carrier aggregation.