Resource integration is a central idea within Service-Dominant Logic, but there has been little empirical research on this aspect of theory. This study explores resource integration between marketing agencies and their clients. Nine case studies were developed, using a dyadic approach, of interviewing clients and members of their agency teams. This was followed up with presentations and workshops with over 200 practitioners that validated the findings and added new perspectives. The key operant resources in the client/agency context were identified. The study suggests that resource enhancement and development, as a result of integration, is important. For agency/client research, resource integration and development brings new perspectives complementing existing relationship approaches to research. The findings have implications for relationship marketing theory across B2B contexts and the discourse of co-creation suggests a way for practitioners to discuss how to work together effectively.