This work investigates the use of Time Reversal (TR) applied to UWB systems for communication and positioning applications. Potential performance boosts, that are achievable over a single UWB communication link by the sole adoption of TR, are investigated. In the case of multiuser UWB communications, it is shown that TR modifies the distribution of Multi User Interference (MUI) and that further performance improvement can be obtained by adapting the receiver to the specific MUI distribution characteristics. As regards UWB positioning, an enhancement in position estimation accuracy can be achieved when TR reinforces DOA estimation thanks to increased robustness to decreased homogeneity in the propagation medium.