With the social context of collaborative networks becoming increasingly important, research has broadened the traditional concept of competitiveness to include and emphasize 'soft' elements, like social capital. The social capital concept can be attained in two different contexts: intra and inter-groups. The objective of this study is to identify inter-organizational social capital elements and the relationship with collaborative network competitiveness. We intend to provide answers to these questions: (i) what are the elements that explain inter-organizational social capital? (ii) how are these elements related to competitiveness? (iii) what organizational characteristics facilitate social capital formation? A survey was conducted in the enterprises from the Brazilian Wine Industry Cluster. The data were analyzed using factorial analysis and bivariate correlations. The results point out three social capital factors that correspond to the social capital dimensions found in literature: structural, relational and cognitive. The research shows that the correlations among social capital dimensions and competitiveness are strong and significant, specially the structural and relational dimensions. Finally, implications for research and managerial practice were discussed.