Methods of transmitting a control signal using efficient multiplexing are disclosed. One of the method includes the steps of multiplexing a plurality of 1-bit control signals within a prescribed time-frequency domain by code division multiple access (CDMA) and transmitting the multiplexed control signals, wherein a plurality of the 1-bit control signals include a plurality of the 1-bit control signals for a specific transmitting side. Accordingly, reliability on 1-bit control signal transmission can be enhanced.