Method and apparatus for mitigating intermodulation distortion effects in frequency division multiple access (FDMA) communications systems. In one embodiment, an effective transmit power level is determined for each communication signal to be transmitted, and signals are allocated to frequency channels such that a smooth tapering of transmit power levels across contiguous frequency channels is achieved. Such smooth power tapering across frequency channels minimizes the possibility that two high power signals will generate an intermodulation distortion product sufficient to disrupt transmission of an immediately adjacent low power signal. In another exemplary embodiment, communication signals are allocated such that high power signals are positioned near a frequency band center, while low power signals are positioned near frequency band edges. As a result, intermodulation distortion between frequency bands in a multiple-band communication system is also minimized.