Rheumatic heart disease (RHD) is an important cause of disability and death in low- and middle-income countries. However, evidence-based interventions have not been implemented systematically in many countries. We present a RHD Needs Assessment Tool (NAT) that can be used at country or regional levels to systematically develop and plan comprehensive RHD control programs and to provide baseline data for program monitoring and evaluation. The RHD NAT follows a mixed-methods approach using quantitative and qualitative data collection instruments. Evidence is mapped to a conceptual model that follows a patient through the natural history of RHD. The NAT has 4 phases: 1) situational assessment; 2) facility-based assessment of epidemiology and health system capacity; 3) patient and provider experience of RHD using ethnographic methods; and 4) intervention planning, including stakeholder mapping and development of a monitoring and evaluation framework. The RHD NAT is designed to paint a comprehensive picture of RHD care in an endemic setting and to identify the major gaps to disseminating and implementing evidence-based interventions.