A method for transmitting uplink control information in a carrier aggregation environment, the method includes: calculating n pieces of response data, each having 1 bit or 2 bits, for n subframes received from an enhanced Node B (eNB) through n downlink component carriers and decoded by a User Equipment (UE); calculating k bits of integrated response data by applying a mapping rule reflecting a weight given to a downlink component carrier of each of the n pieces of response data; and performing a block coding of the integrated response data to produce encoded integrated response data, and transmitting the encoded integrated response data to the eNB.