A method and apparatus are provided for frequency synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) system, wherein the method includes the steps of transmitting OFDM symbols in such a manner that a data symbol size of a particular OFDM symbol in each frame is set to be smaller than a data symbol size of a typical OFDM symbol within the frame, receiving the OFDM symbols and calculating respectively, correlation coefficients of the particular OFDM symbol based on both a time interval of corresponding data symbols and a time interval of data symbols of the typical OFDM symbol, taking respectively phases of corresponding correlation coefficient calculated from the particular OFDM symbol and estimating a decimal part of a frequency offset, and determining an integer partof the frequency offset corresponding to the decimal part of the frequency offset, thereby estimating an entire frequency offset and acquiring the frequency synchronization.