Labour migration is often a migration from geographical peripheries to the geographical centre – like in the last large migration of Polish workers from the peripheral member-state of the UE to its core economies. Yet, very often labour migration is a migration to the peripheries of labour market – labour immigrants usually take up the jobs in the less prestigious industries, in a secondary labour market, self-employ, or take undocumented work. Sometimes it is even a migration from the core to the periphery of labour market – if educated migrants due to the process of de-skilling take up the jobs requiring no, or small qualifications. Trade unions have ambiguous position towards immigrant workers whose presence is often perceived as a cause of lowering of work conditions. On the other hand, some trade unions work hard to integrate immigrant workers into their structures and perceive them as new possible allies. The question of labour movement within the European Union and the labour immigration to European member-states is both an important topic of a public debate but is also an important research site.