Background and objectives: Identifying qualified managers is one of the challenges facing organizations. Given this challenge, the aim of the study was to present a model and identify barriers to succession with a mixed method approach in the I. R. I. Police Command Headquarters. Methodology: In this mixed method study, the theme analysis was used in the qualitative phase and descriptive-survey method was used in the quantitative phase. For this purpose, in the qualitative section, 32 experts and inspection experts of the I. R. I. Police headquarters were selected by targeted sampling method. In the quantitative phase, 250 staff experts and independent subordinate units were selected through a simple random sampling method and a researcher-made questionnaire was distributed among them. Content validity, composite structure and reliability, and Cronbach's alpha coefficient were confirmed. Hierarchical methods have been used to rank variables. Findings: Findings of the research showed that the barriers to succession in I. R. I. Police in order of their priority are: the component of management with coefficient of 0. 5748, organizational structure with coefficient of 0. 3461, performance evaluation with coefficient of 0. 0557, recruitment and employment with a coefficient of 0. 0123, training with coefficient of 0. 0046, and appointment and promotion with coefficient of 0. 0035. In the management sections: Fear of the manager of the succession program, Structure: Emphasis on the executive capacity of the succession program, Performance evaluation: Inadequate evaluation of performance within the Islamic government, Recruitment: Ambiguity in the role, and in the Training section: Emphasis on transferring religious teachings they. Results: In order to have a set of people who can have suitable successors for current managers, the I. R. I. Police organization must take important obstacles into considerations, and senior managers, with their support of the category of succession, play an important role in achieving the organization's goals.