Trends in Eastern Europe, with particular emphasis on Poland, are used in this article to analyse offshoring as a form of social dumping. Neoliberalisation and globalisation generate and utilise the mobility of both capital and labour. Meanwhile, labour migration is presenting a challenge to the observance of labour rights. Present-day methods of capital accumulation rely on the search for cheap labour and the relocation of production to territories that do not protect workers’ rights. Effective defence of labour rights must take place at the transnational level, where most capital is generated. Trade unions need to cross national borders in order to move social activity into this area. The defence of workers’ rights must go hand in hand with the struggle against nationalism and racist prejudices. In this context, migrant workers become one of the main potential driving forces of the modern global proletariat.