The present description relates to a wireless communication system, and more particularly, discloses a method and a device for efficient feedback in a wireless communication system supporting multiple antennas. According to one embodiment of the present invention, the method for transmitting channel status information on a downlink transmission through an uplink, in the wireless communication system, comprises the following steps: transmitting a rank indicator (RI) in a first subframe; transmitting a first precoding matrix index (PMI) in a second subframe; and transmitting a second PMI and channel quality information (CQI) in a third subframe, wherein the precoding matrix to be applied to the transmission of the downlink can be determined by a combination of the first and second PMIs.