This announcement solicits applications for the 2017 Health Care Delivery System Innovations for Children with Medical Complexity cooperative agreement. Children with medical complexity (CMC), a subgroup of children and youth with special health care needs (CYSHCN), have generally been characterized as “children with substantial family-identified needs, characteristic chronic and severe conditions, functional limitations, and high health care use” (Cohen et al. Pediatrics 2011). The purpose of this initiative is to develop and implement innovative care and payment models for such children and youth using a Collaborative Improvement and Innovation Network (CoIIN) approach, which is adapted from Peter Gloor’s collaborative innovation network (COIN) model (Gloor, 2006). Through collaborative learning, a CoIIN made up of teams of families of CMC, pediatric primary and specialty care clinicians, leaders of integrated health care delivery systems and/or freestanding children’s hospitals, state Title V CYSHCN and Medicaid leaders, and other relevant stakeholders from participating states will work together to test strategies and build evidence for optimizing high quality, cost-effective, family-centered care for CMC.