This thesis starts from the description of two main concepts: 'poverty' and 'vulnerability to poverty'. It first presents the main definitions available in the existing literature and draws a basic premise: vulnerability has to be accounted for as likelihood and severity of future poverty (in other words, as the ex-ante perspective of the risk for an individual to become poor). It then lists the main indices used to measure vulnerability to poverty and poverty itself, setting the ground for an empirical application to the Italian panel data of households' income from 1994 to 2001. The final aim of this work is to provide evidence of the necessity to give risk and uncertainty a central role in the political and economic measures to face current destitution.