The present invention relates to a method of transmitting/receiving a signal by a UE in a wireless communication system supporting carrier aggregation. The method includes the steps of: receiving a configuration for aggregating a component carrier in a frequency division duplex (FDD) mode and a component carrier in a time division duplex (TDD) mode; and transmitting/receiving a signal using a primary component carrier and a secondary component carrier determined according to the configuration, wherein the primary component carrier and the secondary component carrier support different modes.