In recent years, there has been increasing interest in applying multicarrier (MC) / code division multiple access (CDMA) system for wireless personal and multimedia communication applications. In this paper, we evaluate the performance of an OFDM/CDMA communication system in frequency domain using autoregressive(AR) modeling. Owing to AR modeling, the transmission channel can be modeled more close to the realistic mobile radio environment based on measured data and also we can save enormous simulation time. We assess the performances of the OFDM/CDMA system corresponding to the variation of SNR and the number of users. transversal filter(DTF). The response of the filter is resulted from the statistics of the measured amplitudes, delays, and phases of the multipath propagation. The taps of DTF are chosen to generate the recommended rms delay spread of a specific channel. Whereas, the frequency domain model is based on reproducing the frequency response of the channel. This model has been generated by an autoregressive(AR) process. The advantage of using the frequency domain model over time domain model is that the former uses fewer parameters and saves us considerable simulation time especially in the case of multicarrier system simulation. Many previous papers have evaluated the performance of OFDM/CDMA systems in Rayleigh or Rician fading channel. However, the trial of performance evaluation of an OFDM/CDMA system in a realistic channel condition has not been performed yet. In this paper, the transmission channel is modeled as AR process and more close to the realistic mobile radio environment based on measured data from Turin[9] and Suzuki[10]. We evaluate the performance of an OFDM/CDMA communication system in frequency domain using AR process corresponding to the variation of SNR and the number of users.