The population policy system in Iran has gone through four periods with different policies. In the current period, which has been about 15 years, in response to the consequences of the decline in fertility rates, the policy of population rejuvenation is being considered. Studies indicate that population rejuvenation in Iran in the form of the law "Exaltation of the Family and Youth of the Population" has not been successful. This research aimed to investigate the factors of inefficiency of population rejuvenation policy and was conducted using library and field studies and qualitative data-based research method. Qualitative data were collected through in-depth interviews with research participants and through Clark's approach, different dimensions of Iran's population rejuvenation policy were identified by drawing different maps. The findings show that the factors of inefficiency of Iran's population rejuvenation policy; The challenges are the policy-making process (formulation, implementation and evaluation) and environmental challenges (social, economic, cultural, managerial and infrastructural). Therefore, considering the complexity of the population and despite numerous climatic, social and cultural differences; various policies and incentives should be implemented and it is recommended to prioritize the rejuvenation of the population, use global experiences and carefully implement the strategies and solutions of researchers.