Abstract: This article explores trade union strategies regarding the problems of the labour market segmentation in Poland, in particular the expansion of precarious (nonstandard and low-paid) forms of employment. The empirical basis of the article are the results of research in four sectors (steelworks, health care, construction and the retail sector), carried out in 2015-16, based on expert interviews with the representatives of trade unions, employers and state administration. Data analysis makes it possible to answer the question about the impact of diversified bargaining power (structural and associational power) in the sectors studied on the forms and efficiency of trade union strategies regarding the precarisation of employment. We claim that despite the shift of trade union activities from the level of collective bargaining to the political and discursive levels, the efficient ways of counteracting the labour market segmentation would require to strengthen structural power of workers which is only partially dependent of trade union strategies.