Ultra wideband (UWB) systems must coexist with other narrow band systems over the same frequency band. The spreading gain of UWB signals might not be sufficient to mitigate narrow band interference, because of the stringent power limitations on UWB. Due to the relatively high sampling frequencies at which UWB systems must operate, traditional digital narrow band interference (NBI) cancelation techniques used in other wideband applications cannot be practically implemented for UWB. Moreover, in the presence of an unmitigated interferer, the quantization process of analog-to-digital (A-to-D) conversion might completely overwhelm the UWB signal. The need thus arises for NBI techniques preceeding the Ato- D operation and specifically tailored for UWB. This paper discusses three potential approaches to UWB NBI: A partially analog front-end NBI canceler based on a linear transversal filter, an interference mitigation technique using real time Fourier transform processing, and interference cancelation exploiting spatial antenna diversity.