Vulnerability has become an integral part of any deprivation assessment. In this paper we take a fresh look at measuring vulnerability, where we separate out the identiÖcation part of whether an individual is vulnerable from the aggregation part as has been done in the multi-dimensional poverty context. In doing so, we have also been able to deal with one of the crucial problems that we see in the multi-dimensional context, which is that of weights used on the di§erent dimensions under aggregation. In this case the probabilities are used as the natural weights. We axiomatically characterize this new measure of vulnerability and thus also provide a theoretical underpinning to many of the empirical applications in this Öeld.