This paper contributes to the understanding of vulnerability related to lone parenthood in Switzerland. Vulnerability is a dynamic process during which individuals experience falls and lose resources, but might also rise and gain empowerment as an outcome of different coping and adaptation processes. The population of lone parents is increasingly heterogeneous in terms of social background and available resources to cope with the challenges posed by a new household arrangement. This implies that the experience of lone parenthood varies substantially across social groups. Such heterogeneity represents a new issue for the definition and the measurement of the relative disadvantage of lone parents and their families. Switzerland is an interesting case study because of the weak work-family reconciliation policies and the institutional configuration that discourage female labour market participation. We discuss how the transition to lone parenthood may translate in additional strains for those parents who have to face the increase in family and work responsibilities alone. We use data from different sources to describe a range of life domains in which lone parents may become vulnerable.