ABSTRACT BACKGROUND: Diagnostic services are highly critical in the success of treatment processes, overly costly nonetheless. Accordingly, hospitals generally seek the private partnership in the provision of such services. This study intends to explore the incentives owned by both public and private sector in their joint provision of diagnostic services under the public-private partnership agreement. METHOD: A qualitative, exploratory study was employed in Tehran hospitals from October 2017 to March 2018. Around 25 face-to-face, semi-structured interviews were conducted with the purposively recruited hospital managers, heads of diagnostic services and managers of private companies. Interviews were transcribed and analyzed using conventional content analysis, assisted by "MAXQDA-12". RESULTS: Three main categories and nine sub-categories represented the incentives of public sector, and four main categories and seven sub-categories signified those of private sector. The incentives of public sector included the status-quo remediation, upstream requirements, and personal reasons. As such, the individual, social and economic incentives and legal constraints were driving the behavior of the private sector. CONCLUSIONS: Financial problem and gain were the most noted incentives by the partners. Attention to the either side’s incentives and aims is likely to ensure the durability and effectiveness of such partnerships in the health sector.KEYWORDS:  Public-Private Partnerships, diagnostic Services, Hospital, Incentives, Iran