The recent discussion about "risk society" is mostly focused on risks coming from the technological and scientific development, while new kinds of risk are emerging in everyday life as a consequence of economic, social and demographic current changes. These risks have not found yet an adequate consideration in sociological thinking. To fill this gap, the paper illustrates the concept of vulnerability as a tool for understanding the contemporary forms of social precarity and flexibility. The main argument is that vulnerability is a new social risk that is characterized by: high probability of occorrence (while traditional risks are relatively rare events), permanence of its effects on individuals (while traditional risks are frequently temporary events), precarity of the social position associated with these risks (while the individual exposition to traditional risks is statistically valuable). Vulnerability may also depress what Sen calls the individual functioning, making the aknowledgement of risks and the capacity of choice more difficult than in the past. AS a consequence, even the sense of continuity and personal identity of people exposed to vulnerability are also mined. Lately, the paper considers the difficulties of modern welfare systems to provide people with ad adequate protection from vulnerability.