Declining unionization in many countries have motivated studies to get a better understanding of what factors that inﬂuence the decisions of young workers to join trade unions. In particular, it is interesting to examine the role of union membership in close family. It is widely recognized that individual choices are affected by intergenerational transmission of preferences regarding political orientation (Jennings et al. 2009), education (Holmund et al. 2011) and receipt of welfare insurance (Dahl et al. 2014), to mention some. Is this also the case for union membership? Bryson and Davies (2018) finds that the decision of young workers in Britain on whether or not to join a union is influenced by their parents’ union membership. In particular, their study reveals that young workers are 29 per cent more likely to join a union if one of their parents is a union member, and 87 per cent more likely to join a union if both are union members, compared to individuals with no unionized parents (pp. 12-13). To what extent do we observe the same effects in Norway? In this study, we will use register data covering all employees in the period 2000-2019 to investigate the impact of organized parents, siblings and spouse for the individual choice of becoming a union member.