This paper uses a survey of French firms active in R&D to identify the determinants of the trade-off between R&D subcontracting and R&D cooperation. We observe that R&D subcontracting is more likely than R&D cooperation when the partner is chosen on objective criteria, such as prices, quality certificates and geographic proximity. Subcontracting relationships also involve less uncertainty, are less likely to lead to patent deposits and less frequently involve public research institutions. These results are coherent with the hypothesis that R&D subcontracting mainly concerns standardized R&D processes.R&D cooperation, R&D subcontracting, organizational choices,