The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and an apparatus for reporting channel state information, the method and the apparatus comprising the following steps: measuring downlink signals from a plurality of base stations; feeding back a first channel state information on a first base station in subband units, wherein the first channel state information includes identification information for indicating a corresponding subband; and feeding back a second channel state information on a second base station in subband units, wherein the subband which corresponds to the second channel state information is set to be identical to the subband which corresponds to the first channel state information, and wherein the second channel state information does not include identification information for indicating the corresponding subband.