In this first paper in a series of four papers on midwifery, we aimed to examine, comprehensively and systematically, the contribution midwifery can make to the quality of care of women and infants globally, and the role of midwives and others in providing midwifery care. Drawing on international definitions and current practice, we mapped the scope of midwifery. We then developed a framework for quality maternal and newborn care using a mixed-methods approach including synthesis of findings from systematic reviews of women's views and experiences, effective practices, and maternal and newborn care providers. The framework differentiates between what care is provided and how and by whom it is provided, and describes the care and services that childbearing women and newborn infants need in all settings. We identified more than 50 short-term, medium-term, and long-term outcomes that could be improved by care within the scope of midwifery; reduced maternal and neonatal mortality and morbidity, reduced stillbirth and preterm birth, decreased number of unnecessary interventions, and improved psychosocial and public health outcomes. Midwifery was associated with more efficient use of resources and improved outcomes when provided by midwives who were educated, trained, licensed, and regulated. Our findings support a system-level shift from maternal and newborn care focused on identification and treatment of pathology for the minority to skilled care for all. This change includes preventive and supportive care that works to strengthen women's capabilities in the context of respectful relationships, is tailored to their needs, focuses on promotion of normal reproductive processes, and in which first-line management of complications and accessible emergency treatment are provided when needed. Midwifery is pivotal to this approach, which requires effective interdisciplinary teamwork and integration across facility and community settings. Future planning for maternal and newborn care systems can benefit from using the quality framework in planning workforce development and resource allocation. Copyright © 2014 Elsevier Ltd. All rights reserved.