BackgroundOccupational health services may have a strategic role in the prevention of sickness absence, as well as in rehabilitation and return to work after sick leave, because of their medical expertise in combination with a close connection to workplaces. The purpose of this study was to explore how employers and occupational health service providers describe their business relations and the use of occupational health services in rehabilitation in relation to the organization of such services. The study uses a theoretical framework based on social capital to analyse the findings.MethodsInterviews and focus groups with managers with Swedish public employers (n = 60), and interviews with occupational health services professionals (n = 25).ResultsEmployers emphasized trustful relationships, local workplace knowledge, long-term contracts and dialogue about services for good relationships with occupational health providers. Occupational health providers strove to be strategic partners to employers, promoting preventive work, which was more easily achieved in situations where the services were organized in-house. Employers with outsourced occupational health services expressed less trust in their providers than employers with internal occupational health provision.ConclusionsSocial capital emerges as central to understanding the conditions for cooperation and collective action in the use of occupational health services, with reference to structural (e.g. contracts), relational (e.g. trust) as well as cognitive (e.g. shared vision) dimensions. The study suggests that attention to the quality of relationships is imperative for developing purposeful occupational health service delivery in rehabilitation and return to work.