Financial stress is the root cause of many adverse health outcomes among poor and low-income children and their families, yet few clinical interventions have been developed to improve health by directly addressing patient and family finances. Medical-Financial Partnerships (MFPs) are novel cross-sector collaborations in which health care systems and financial service organizations work collaboratively to improve health by reducing patient financial stress, primarily in low-income communities. This paper describes the rationale for MFPs and examines eight established MFPs providing financial services.