The present invention relates to a wireless communication system, and in particular, to a method and an apparatus for transmitting a downlink reference signal in a wireless communication system that supports multiple antennas. The method for transmitting a reference signal for a maximum of eight antenna ports according to one embodiment of the present invention comprises: in a base station, mapping part of a common reference signal for a maximum of four antenna ports into a downlink subframe that includes a 1st slot and a 2nd slot; in the base station, mapping a channel status information reference signal for the maximum of eight antenna ports into the downlink subframe, according to a preset pattern; and in the base station, transmitting the downlink subframe into which the common reference signal and the channel status information reference signal have been mapped, wherein the preset pattern defines the channel status information reference signal for the maximum of eight antenna ports to be mapped onto two OFDM symbols of the data region in the downlink subframe, and wherein part of the common reference signal for the maximum of four antenna ports is limited to the common reference signal for a maximum of two antenna ports.