An adaptive interference canceller for use in a dual polarized radar system for receiving cross-polar and like-polar signals and generating an output signal corresponding to the received cross-polar signal with a like-polar interfering component cancelled therefrom. A modified adaptive filter is provided with a self-adjusting impulse response conforming to a least means square adjustment cancelling the influence of the like-polar signal, which is generally much stronger on the cross-point signal. The resulting output has a high target-to-clutter ratio and therefor a high probability of detection.