In low- and middle-income countries (LMICs), 93% of the population lacks safe, timely, and affordable access to cardiac surgical care when needed. As countries slowly build or expand local, independent cardiac centers, non-governmental organizations (NGOs) partially bridge the gap in cardiac surgical care delivery in LMICs. However, little is known about the current scope of cardiac NGOs. Here, we perform an analysis of active NGOs involved with the delivery of cardiac surgical services in LMICs or for patients from LMICs. Cardiac surgery NGOs were identified from medical literature, established NGO databases, and Google Scholar searches. The search was performed between December 2019 and May 2020. NGOs whose websites were not updated or described missions or projects taking place no later than 2015 were considered inactive. Eighty-six NGOs are actively providing cardiac surgery services in LMICs or treating patients from LMICs. Five NGOs performed adult cardiac surgery only, 56 performed pediatric cardiac surgery only, and 25 performed both adult and pediatric cardiac surgery. NGOs originated from 23 different countries and were operational in a total of 111 countries, 96 of them being LMICs. Fifty-three NGOs reported data on annual surgical volume, of which half performed less than 50 operations per year. NGOs effectively address the burden of cardiac surgical disease in LMICs and contribute to local capacity-building. Increased, more detailed, and standardized reporting of the impact and outcomes of NGOs is necessary to better understand annual cardiac surgical volume and to support local centers working towards independent services.