The involvement of representatives from multiple organizational functions is recommended for developing close relationships with key customers and suppliers. The way in which cross-functional interactions are managed can determine the success or failure of a buyer-supplier relationship in terms of the ability to co-create value. The goal for this research was to provide a deeper understanding of the role of cross-functional involvement in fostering the co-creation of value in interorganizational buyer-supplier relationships. Two pairs of relationships with different levels of cross-functional involvement were compared. Data were collected from interviews with 46 managers and from financial records. Value co-creation was estimated in financial terms and was compared with the managers’ perceptions of value. The results indicate that the relationships in which more cross-functional initiatives were conducted achieved higher levels of value co-creation. However, managers normally did not use financial measurements that captured total value co-creation. Without sound measurements of value co-creation, managers base their decisions on price or perceptions that can be inaccurate, incomplete or biased. The qualitative data collected from the interviews were used (1) to describe the reasons for managers not measuring value co-creation in financial terms, (2) to explain the mechanisms by which value was co-created when more functions were involved, and (3) to identify the challenges and the success factors associated with implementing cross-functional teams with key customers and suppliers. Managers can use the research findings to quantify the financial value of buyer-supplier relationships. With this information, customers and suppliers can be segmented and managed based on total value co-creation and not on perceptual measurements of value. The findings can be used to demonstrate top managers and functional managers the financial value of developing cross-functional relationships and to gain their commitment to develop cross-functional relationships. Managers can use the findings to implement cross-functional teams that foster the co-creation of value with key customers and suppliers. Past research on relationship marketing was conducted using perceptual data from few managers from one side of the dyad. The development of better measurements of the financial impact of marketing investments was identified as an imperative for improving marketing thought (Brown et al. 2005). Academics will find this research useful because financial measurements were developed to determine the value of buyer-supplier relationships. Also, the literature on value co-creation and on cross-functional teams was taken to the next step by demonstrating the relevance of developing cross-functional teams in business-to-business contexts. Opportunities for further research on value co-creation were described