The document “Communicable Disease Surveillance and Response Systems: A Guide to Planning” is a World Health Organization (WHO) guide designed to help countries develop and strengthen national surveillance and response systems for communicable diseases . It explains why surveillance is essential for early detection of outbreaks, informed decision-making, and effective public health action, especially in the context of the revised International Health Regulations (2005). The guide provides a structured approach to strategic and operational planning. It outlines how countries should assess their existing systems, define a vision and goals, identify expected key result areas (EKRAs), prioritize activities, set realistic targets, allocate resources, and monitor progress. It also includes practical tools such as templates, worksheets, and examples to support ministries of health in organizing planning workshops and developing multi-year strategic plans and annual operational plans. Overall, the document serves as a practical framework to improve preparedness, early warning, and response to public health emergencies.