Abstract We propose a minimum mean squared error (MMSE) decision feedback equalizer (DFE) for pulse position modulated (PPM) signals in the presence of intersymbol interfer-ence (ISI). While traditional uses of PPM may not have ISI, PPM is a candidate modulation scheme for ultra wideband (UWB), and may experience ISI in that application. First, we review previous work on the subject which used the zero-forcing criterion under strict assumptions about the channel and equalizer lengths. Then, we derive a computationally efficient MMSE equalizer which removes these restrictions, and is suitable for use with stochastic gradient descent algorithms. Finally, we demonstrate the performance of the proposed equalizer with simulations.