During the 1950s and 1960s Puerto Rico's industrial transformation was accompanied by social stability and relatively peaceful labour relations, which were essential for a development programme dependent upon foreign investments. The state took a central role in this process, as it guided economic activity and mobilised vital human and material resources. However, by the late 1960s profound changes in the island's political economy threatened this state-guided development programme. This essay traces the history of Puerto Rican economic change and the relationship between industrial transformation and the state's capacity to manage the operation of the economy, particularly industrial relations up to the late 1970s. Four features of this process will be examined: (1) labour relations during the early phase of industrialisation; (2) the changes in the economy resulting from the expansion of capital-intensive industrial sectors; (3) the impact of these changes on the state's capacity to manage the political economy, particularly its fiscal policy; and (4) how these changes altered the nature of state-labour relations.