Disclosed is a system and method for transmitting/receiving a signal in a communication system. In the system and method, a base station transmits data to a first relay station, which is connected directly thereto from among relay stations belonging to a first relay station group, through a first frame interval, and transmits data to a second relay station, which is connected directly thereto from among relay stations belonging to a second relay station group, through a second frame interval subsequent to the first frame interval. In the first frame interval or the second frame interval where no data is received from the base station, each of the first and second relay stations transmits data to a next relay station connected directly thereto within the same relay station group, and communicates data with a mobile station in direct communication therewith.