An apparatus and method for canceling ISI in a broadband wireless communication system are provided. In a transmitter of the broadband wireless communication system, a controller acquires a CP length, a puncturing pattern, and a time sample interval according to a delay spread. A puncturer punctures coded data in the puncturing pattern. An IFFT processor IFFT-processes the punctured coded data and outputs sample data. A CP inserter generates an OFDM symbol by inserting a copy of a last part of the sample data before the sample data. Here, the length of the last part of the sample data is equal to the CP length. A D/A converter converts the OFDM symbol to an analog signal at a sampling rate determined by the time sample interval.