— One of the main concerns in ultra wide band (UWB) impulse radio (IR) technology is the presence of severe multiple access interference (MAI). Efficient receivers should therefore be capable of deleting, or at least mitigating, this effect. Based on the observation that MAI has an impulsive structure, we model it as a Gaussian mixture random process, to derive the optimum receiver accordingly. By carefully simplifying parts of the resulting algorithm, we are able to propose a receiver approach which is efficient in mitigating MAI, while having low computational complexity. Its effectiveness is compared to state of the art approaches by simulations in a realistic scenario.