Disclosed herein are a transmission apparatus, a reception apparatus and a transmission/reception method for an OFDM-based broadcasting system. The transmission apparatus includes multiple transmission frame generation units for generating multiple transmission frames from transmission data, an extended frame combination unit for generating an extended frame by combining the multiple transmission frames so that the multiple transmission frames are adjacent to each other based on a frequency, an extended OFDM modulation unit for modulating the extended frame and then generating a modulated signal, and a frequency up-conversion unit for performing frequency up-conversion on the modulated signal and generating a transmission signal, wherein each of the transmission frame generation units includes a data input unit for receiving transmission data, a channel-encoding unit for encoding the received transmission data and generating encoded data, and a framing and interleaving unit for framing and interleaving the encoded data and generating a transmission frame.