Orthogonal frequency division multiplexing (OFDM) is a special case of multicarrier transmission, where a single high rate datastream is transmitted over a number of lower rate datastream. The demand for high-speed mobile wireless communications is rapidly growing. OFDM technology is a key technique for achieving the high data capacity and spectral efficiency requirements for wireless communication systems nowadays. In this paper, we investigate the performance of OFDM systems with different orders of Quadrature Amplitude Modulation (QAM). We consider OFDM scheme with an Additive White Gaussian Noise channel (AWGN) and analyze their performance in terms of the bit error rate (BER) in the system.