Discussions of the politics of immigration in Europe have focused on the apparent success of Radical Right Parties (RRP) in exploiting migration-related issues. The potential impact of RRPs upon mainstream political parties as the latter toughen their policies in response has been a major topic of debate. However, radical left parties (RLPs) have received relatively little attention. As significant niche players in many countries, such parties face a dilemma in positioning themselves on migration related issues. On the one hand they promote an inclusive politics of solidarity, universalism and diversity against the trend towards more -restrictive policies. On the other, they may share at least some sources of support with RRPs (notably the traditional working class) and a concern about the effects of immigration on their support. This paper analyses the way in which they have responded to this dilemma, particularly in those countries where RRPs have been successful.