Background: To gain and maintain stable competitive advantages, hospitals are currently seeking novel strategies for Patient Satisfaction Development (PSD). To this end, hospitals are required to establish strategies for improvement and provide basic platforms; one of these strategies is Internal Marketing (IM). This type of marketing typically demands customer-oriented behavior and thinking by all hospital staff in terms of dealing with patients. Accordingly, the current research recommends a simulation pattern for PSD within hospitals in Ardabil Province, Iran, considering the predominant factors affecting IM. Methods: This study, utilizing a qualitative-quantitative research design, was conducted on a statistical population of 17 theoretical (the university professors) and experimental (hospital managers) experts. The sampling technique was of the non-probability type and purposive, and the data collection tools were interviews and questionnaires. In the qualitative phase, the main themes and sub-themes of IM in the hospitals of Ardabil Province, Iran, were initially identified by thematic analysis. Then, in the quantitative phase, the major factors were prioritized via the fuzzy Delphi method, and finally, the effects of IM on PSD were simulated through agent-based modeling. Data analysis in the qualitative phase was done with MaxQDA 20 software, and Microsoft Excel and AnyLogic 8.9 were operated in the quantitative one. Results: Based on the study results, 35 primary codes, 12 sub-themes, and three main themes (organizational, occupational, and individual) were obtained. In light of this, the organizational factors were introduced as the most effective ones. Besides, the study results suggested that the PSD prospect in the hospitals of Ardabil Province, Iran, reached 70 % at the end of the simulation. Conclusion: According to the study results, it is suggested that hospital managers devote much attention to the effective factors in IM, specially the organizational ones, as they play a leading role in PSD.