This study describes the relationship between the culture of trade unions, solidarity and sustainable development. The major objective is to show how the culture of trade unions affects their perceptions of sustainable development. This has been done through a comparative, interdisciplinary study of LO in Norway and ACFTU in China. The main finding is that although the nature and goal of trade unions and their culture of solidarity are well aligned with the ideal of sustainable development, evidence shows that little work is done in practice. It has been argued that trade unions have not been willing to carry the burden in order to change consumptions patterns or the mode of production. The reasons for this can be found in the culture of the trade unions. This is explained by constructs of nature basically as a source of work and income. By misreading the concept of solidarity with unbalanced emphasis on traditional values of securing employment, improving living conditions and wages, trade unions have ignored the importance of environmental aspects and sustainable development for the good of the workers. If trade unions continue to overlook their solidarity duties, workers will remain economically and environmentally victimised. To acknowledge the sustainable challenges, trade unions might have to return to their ideological roots as a social movement.