Wireless technologies, such as satellite, cellular, and wireless internet are now commercially driven by ever more demanding consumers, who are ready for seamless integration of communication networks from the home to the car, and into the office. There is a growing need to quickly transmit information wirelessly and accurately. Engineers have already combined techniques such as orthogonal frequency division multiplexing (OFDM) suitable for high data rate transmission with forward error correction (FEC) methods over wireless channels. In this thesis, the performance of a working OFDM system is enhanced by adding turbo coding with Binary Phase Shift Keying modulation (BPSK). Simulation is done under AWGN and flat fading Rayleigh channel environments and frequency selective fading channel. The temporal variations in the simulated wireless channel are due to the presence of Doppler frequency, i.e. relative motion between transmitter and receiver. The simulation of OFDM and TCOFDM systems are achieved by MATLAB version 0.7. The wideband system has 64 and 512 data sub-carriers; each is individually modulated according to channel state information acquired during the previous burst. The objective of this work is to investigate the effect of Turbo Coding to the OFDM system as a preceding stage to the OFDM. In spite of the improvement of turbo codes for the OFDM system but Turbo code has a drawback represented in its complexity in the design and also the decoding time is long. The simulation results shows that, the presented system which is Turbo Coded-OFDM (TCOFDM) outperforms the OFDM system only especially at high SNR ratios. Hence maximum gain of 17 dB is obtained at 10-4 BER using TCOFDM system in comparison to OFDM system.