A method for receiving aperiodic channel status information (CSI) report in a wireless access system, the method performed by an evolved Node-B (eNB) and comprising: transmitting a radio resource control (RRC) message configuring two or more CSI measurement sets, wherein each of the two or more CSI measurement sets consists of one or more subframes; transmitting an aperiodic CSI request field triggering the aperiodic CSI report via a physical downlink control channel (PDCCH) on a first subframe; and receiving the aperiodic CSI report with CSI on a second subframe, wherein the CSI is associated with a valid subframe which is included in one of the two or more CSI measurement sets, and the valid subframe is defined as a closest subframe from the second subframe in consideration of predetermined condition.