Fault reactivation processes may be precursors of volcanic eruptions. Reactivation is generally due to an increase of fluid pressure, which induces a decrease of the effective normal stress on the fault surface. Historical information from the Vesuvius volcano indicates that faults reactivation occurred during pre-eruptive and eruptive phases. A slip tendency analysis of the Vesuvius faults has been performed with the aim to investigate the potential fault activity associated to an increase of fluid pressure. A detailed mapping of the Vesuvius faults has been performed combining DTM and geological data. Slip tendency of the Vesuvius faults has been calculated using available information about the stress field acting on the volcano. The stress field has been perturbed by increasing the fluid pressure and slip tendency fault maps have been derived for different values of fluid pressure. Results indicate that both surface and seismic monitoring of the Vesuvius faults could provide useful insights into the volcano dynamics evolution allowing to refine assessment of volcanic hazard. ¿ 1999 American Geophysical Union