The present invention relates to a method and apparatus for transmitting data. The method for a terminal to receive downlink data includes the steps of: receiving resource allocation information from a base station; and demodulating the downlink data transmitted through a sub-resource allocation unit allocated on the basis of the resource allocation information, wherein the sub-resource allocation unit is a plurality of resource units included in one resource allocation unit and the downlink data can be demodulated on the basis of a demodulation reference signal (DM_RS).