Provided is an apparatus and method for transmitting/receiving signals in a communication system. A base station allocates a quasi-dedicated control channel (QDCCH) to a first mobile station (MS), and allocates the QDCCH allocated to the first MS, to a second MS for a preset time. An MS receives a QDCCH allocated from the base station. If there is data to transmit to the base station, the MS determines whether the QDCCH is allocated to another MS different from the MS. If it is determined that the QDCCH is allocated to the MS itself, the MS transmits the data to the base station over the QDCCH.