|In this work, results of an analytical analysis to assess the effect of Ultra Wide Band (UWB) emissions on the Worldwide Interoperability for Microwave Access system (WiMAX) are presented. The WiMAX range is evaluated with and without the UWB interference. Free space propagation model is used to calculate the UWB signal power that interferes with WiMAX systems. It is shown that, for the case of single UWB transmitter, WiMAX system can easily tolerate UWB interference when the UWB EIRP is ?83 dBm/MHz or less for a distance between the UWB transmitter and the WiMAX receiver of 1 m or higher at 3.5 GHz frequency in order to have only 5% range reduction. To make this possible, multi band UWB should not transmit in the first and the second bands. This will have a detrimental effect on UWB technology. For 2.5 GHz WiMAX, the range reduction will be 5% when the UWB EIRP is ?87 dBm/MHz.