Background: WHO has undertaken substantial efforts to enhance evidence-based policy-making in the Eastern Mediterranean Region. : The coronavirus (COVID-19) pandemic underscored the importance of strengthening and institutionalizing evidence-informed policy-making. Having sufficient, reliable, and quality evidence available is needed to handle emerging health crises and to build resilient health systems. In the context of WHO mandate to enhance the national institutional capacity of evidence-informed policy- making, WHO EMRO supported the development of case studies to showcase how evidence has been used by the countries to inform decision making in response to COVID-19. Objectives: Document the experiences in using evidence and data to respond to COVID-19 and gather lessons learnt to support the institutionalization of evidence-informed policy-making in the Eastern Mediterranean Region. Methods: Criteria based on a regional framework that integrates various concepts to approach evidence-informed policy-making were used to select topics for case studies. A broad coverage of country profiles was sought, to ensure representation across low-, middle- and high-income countries as well as countries affected by emergencies. A template including ten essential elements for case studies was developed and applied to ensure consistent reporting across the case-studies and to facilitate comparative analysis. Case-studies were drafted by national teams with technical support from WHO. A comparative analysis was conducted by two investigators and reviewed by a third investigator where there were uncertainties or disagreements. Result: 15 case studies from 13 countries in the Eastern Mediterranean were developed. The most common sources of evidence used across these case studies were surveys and routine data. Evidence was used to develop national policies in 10 case studies, and local policies in five case studies. Most policies documented across the case studies focused on vaccination and public health and social measures. Conclusion: Key lessons learned emerged from this exercise: common challenges included the limited availability of national data and of supporting systems for data collection. Community engagement and a multi-sectoral approach at the government level facilitated effective evidence-informed policy-making.