A BSTRACT Background: The global use of the Internet has led to the growth of e-commerce in industries. Similarly, in health care, e-commerce is essential to meeting the high expectations of patients and providing high-quality and affordable health care services in clinics, hospitals, and other health centers. Purpose: This study aimed to prioritize the factors influencing the adoption of e-commerce in hospitals of Tehran (Iran( in 2021 using multi-criteria decision-making techniques. Method: The independent variables included organizational, contextual, environmental, and technological factors, while the dependent variable was e-commerce acceptance. To answer the research question, the data were collected via documentary research method (secondary data) and survey (primary data). The instrument used for the survey was a pairwise comparison questionnaire that was completed by 186 experts selected via random sampling method, based on Morgan’s table, and with respect to inclusion and exclusion criteria. Using these instruments, the factors affecting the adoption of e-commerce were assessed using multi-criteria decision-making techniques and the AHP method. Results: The results of the prioritization of factors affecting the adoption of e-commerce in Tehran hospitals, from the experts’ point of view, showed that the technological criterion (weight: 0.31918) is the most important factor, followed by organizational (weight: 0.30291), contextual (weight: 0.20346), and environmental (weight: 0.17445) factors. The consistency coefficient of the model was 0.021142. Conclusion: The findings indicate that it is possible for doctors, nurses, patients, and medical centers to exploit the benefits of e-commerce in primary care, environmental, financial, organizational, human-related, and technological factors in healthcare.