Disclosed is a method and apparatus for transmitting/receiving control information in a system in which one or more Radio Frequencies (RFs) are used to carry multiple services through a frame constituted by time resources or time-frequency resources. Control information regarding frame configuration information is not transmitted over a separate control channel but over a data channel through which to transmit primary service traffic among all service traffic, and each non-primary service traffic other than the primary service traffic includes control information for a primary service. Thus, even when a receiver changes the current service to a target service, control information necessary to detect the location of the target service in a frame and demodulate the target service can be acquired, and thus a service change can be made without reading a separate control channel.