The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus for a terminal to report channel state information in a wireless communication system, the method comprising: a step of transmitting first channel state information according to a first channel state information (CSI) process for reporting the first channel state information periodically for every first period; a step of transmitting second channel state information according to a second CSI process for reporting the second channel state information periodically for every second period; and a step of dropping the transmission of either the first channel state information or the second channel state information on the basis of the CSI process index of each of the first and second CSI processes in the event the first channel state information transmission timing and the second channel state information transmission timing conflict.