The establishment of research and development (R & D) laboratories by the UK affiliates of overseas-controlled firms was a feature of the R & D landscape throughout the twentieth century and had its origins even earlier. From their foundation they served as sites for international scientific and technological collaboration and exchange. Here I draw on both quantitative and qualitative evidence to examine the research and development activities of overseas multinational enterprises in the UK. This activity has a longer history than most previous commentators have suggested. The integration of at least some R & D facilities into international research networks was already a feature during the inter-war years. This became far more common after the early 1960s, as firms worked hard to integrate previously independent laboratories into coordinated research organizations. Far from being a ‘new collaborative mode’ in the late twentieth century, cross-border networks of industrial laboratories have long contributed to the internationalization of science.