In this paper, we propose a receive diversity method for orthogonal frequency division multiplexing (OFDM) systems with cochannel interference. In the method, combining is done in the frequency domain by using the subcarrier based maximum ratio combining (MRC) method. For MRC, we exploit the power of cochannel interference as well as the power of channel noise. The accuracy of the power estimate of interference plus noise is enhanced by averaging the initial estimates over the correlated subchannels where the coherency between the subchannel gains comes from the limited delay spread of the channel. Simulation results show that the proposed method yields 2-3.5dB gain of signal to noise ratio compared to the conventional MRC method and less than 1 dB difference to the ideal case.