Orthogonal Frequency Division Multiplexing (OFDM) has been adopted by IEEE 802.11's standard as a transmission technique for high data rate in Wireless Local Area Networks (WLANs). Multicarrier modulation is required for wireless communication system. OFDM is multicarrier modulation which provides good spectral efficiency and eliminates intersymbol interference and intercarrier interference. This paper is to simulate OFDM modulator for IEEE802.11a standard. OFDM modulator is simulated using Simulink tool from MATLAB 2012a and System generator tool from XILINX 14.2.