Decision making based on best available research evidence for increasing efficiency and effectiveness of policies is one of the most important concerns of policy makers all over the world and policy-making in health systems is no exception.  This approach, which is known as Evidence-informed policy making (STP), in recent years much attention has been paid to this approach. The objective of this study is to contribute to a wider understanding of (STP) and explain support tools to this policy making in health system. In this review article, different papers, reports and relative books were used in order to gather relevant information. They were identified through searching electronic databases using proper key words and reference scanning of key papers. The data were synthesized using a narrative approach. Systematic process that is explained in this study can be applied to support evidence-informed health policymaking. It highlights the importance and needs for identifying, assessing, synthesis and use of valid and reliable research evidence and provides suggestions regarding with these issues. An evidence-informed policymaking approach can enable policymakers, policy analysers to better communications with researchers. It also allows using relevant and best available evidence timely and effectively. It can facilitate well-informed decision-making process and may result in more effective and efficient policies in health systems.Decision making based on best available research evidence for increasing efficiency and effectiveness of policies is one of the most important concerns of policy makers all over the world and policy-making in health systems is no exception.  This approach, which is known as Evidence-informed policy making (STP), in recent years much attention has been paid to this approach. The objective of this study is to contribute to a wider understanding of (STP) and explain support tools to this policy making in health system. In this review article, different papers, reports and relative books were used in order to gather relevant information. They were identified through searching electronic databases using proper key words and reference scanning of key papers. The data were synthesized using a narrative approach. Systematic process that is explained in this study can be applied to support evidence-informed health policymaking. It highlights the importance and needs for identifying, assessing, synthesis and use of valid and reliable research evidence and provides suggestions regarding with these issues. An evidence-informed policymaking approach can enable policymakers, policy analysers to better communications with researchers. It also allows using relevant and best available evidence timely and effectively. It can facilitate well-informed decision-making process and may result in more effective and efficient policies in health systems.