The Health Technical Working Group (TWG) is open to professionals working in all fields of global health. In the past, the TWG has been led by the Evidence to Action Project and ExpandNet and has had a special focus on systematic approaches to scale up in reproductive health and family planning (FP/RH). Going forward there is now a desire to engage with professionals from a broad range of technical areas of health. The TWG seeks to systematically build on shared experiences and insights on the determinants of sustainable scale up from a wide range of fields of global health, as well as other relevant disciplines including the organization, management, policy and implementation sciences. Current members include individuals from a diverse range of global health and development institutions with an interest in advancing the science and practice of scale-up, such as: regional- and country-level policy makers, program managers, technical support personnel, together with researchers from the public, private, donor and NGO sectors. ExpandNet will continue to lead the group, which will host quarterly meetings focused on critical topics related to scale-up, ensuring the participation of colleagues working on scale up in low- and middle- income countries. Like all CoP Working Groups, participation in the Health TWG is voluntary.