This study examines the role of Social capital dimensions towards resource sharing within R&D cooperation projects funded by the 7th Framework Programme (FP7). Data were collected in a survey of 553 FP7 project participants and analysed using two different social network analysis (SNA) methodologies: Logistic regression quadratic assignment procedure and exponential random graph models. Results showed that all Social Capital dimensions helped to explain partners' resource sharing, although to a different extent. Prior ties were often significant, whilst shared vision and commitment were very frequently positive contributors to resource sharing. Trust was rarely significant, and occasionally detrimental, to partners' resource sharing. Therefore, the FP7 provided a collaborative but opportunistic environment for public and private actors. The novelty of this study derives from the combination of social capital theory with SNA to study intra-project partner relationships, contributing to a better understanding on the diversity of partner relationships within R&D projects.