Introduction & Background: Iran Health Transformation Plan was designed and implemented in 2014 to improve access and quality of public hospital services and reduce patients’ out of pockets. Policy makers should consider both employees’ and customers’ needs to achieve long term positive outcomes. The HTP implementation increased patients’ referrals to governmental hospitals and consequently increased their staffs’ workloads. This study aimed to identify internal marketing factors affecting successful HTP implementation. Materials & Methods: This qualitative study was conducted in 2017. Study population was the managers and workers of teaching hospitals of Tehran city, Iran. Sampling was done purposefully and with maximum variety (N=62). The data was gathered by semi-structured in-depth interviews and was analyzed by content analysis method using the MAXQDA11 software. Results: The HTP had focused on external marketing and the internal marketing is almost neglected. Empowerment, job motivation, and effective communications have great roles in enforcing the internal marketing. Empowerment includes the feeling worthwhile and effective, and training. Job motivation includes proper physical environment, having required facilities and technologies, appropriateness of professionals with workload, rule of laws and regulations, job security, employee participation, perceived organizational support, career promotion, and salary. Effective communication includes decreasing the power distance, easy access of the workers to the managers, and active feedback. Conclusion: This study identify internal marketing factors affecting successful HTP implementation. Health system policy makers and managers may increase the customer-oriented behaviors of the health workforce by applying the internal marketing.