A method for mapping, by a base station, a channel state information (CSI)-reference signal (RS) in a wireless communication system, includes mapping the CSI-RS, for at least one antenna port, to at least one pair of resource elements (REs) per physical resource block (PRB) pair in consecutive orthogonal frequency division multiplexing (OFDM) symbols in a subframe, wherein the subframe includes two slots, and each slot includes six OFDM symbols based on an extended cyclic prefix (CP), and transmitting the CSI-RS to a user equipment (UE) via the at least one antenna port in the subframe.