A method and a user equipment for transmitting uplink control information in a wireless communication system supporting carrier aggregation and operating in time division duplex (TDD) are discussed, the user equipment being configured with a first component carrier (CC) and a second CC having different uplink-downlink configurations, the user equipment being configured to transmit a hybrid automatic repeat request-acknowledgement (HARQ-ACK) response based on channel selection. The method according to an embodiment includes determining and transmitting HARQ-ACK bits. When a value W is 1 or 2, one or more HARQ-ACK bits for the first CC are determined based on min (M1, W) and one or more HARQ-ACK bits for the second CC are determined based on min (M2, W). Min (A, B) represents a smallest number, M1 represents a number of downlink subframes, and M2 represents a number of downlink subframes.