In many countries there has been a move towards more decentralized labour market systems in the 1980s and 1990s. This process has been particularly notable in Sweden. This study analyses the origins of the Swedish decentralization from a historical and comparative perspective. The main emphasis is on ideological motives, linked to a shifting balance of power. The more decentralized Swedish industrial relations become, the greater the likelihood that the power relations between the two main parties change in the employers' favour. Even if internationally determined changes in the organization of work are important, changes in industrial relations still seem to be very much a question of a struggle between the different interests of employers and employees.