Interhospital transfers comprise a significant and increasing proportion of admissions to tertiary care centers. Patient dissatisfaction with the quality of hospital care may play an important role in these trends. The objective of this study was to describe why and how patients and surrogates request transfers to tertiary care. We interviewed 32 patients transferred to the Johns Hopkins Hospital, a US tertiary care center, or their surrogate decision-makers using a semi-structured, open-ended, iterative protocol. We used ethnographic decision modeling to develop an influence diagram of the decision. We contrasted subjects' perceptions of situations where patients did and did not request transfer to describe the threshold for requesting transfer. Subjects reported three major influences on the request to transfer to tertiary care: the quality of care at the community hospital compared to the tertiary center; the severity and potential consequences of the current illness; and their relationship with community hospitals, physicians, and tertiary care. Subjects' perceptions of the quality differential between community hospitals and tertiary centers focused on communication and medical errors rather than specialized care, hospital volume, or teaching status. Thresholds for when patients requested transfers were influenced by relationships with community hospitals and physicians and previous experience with tertiary care. This model provides a framework for understanding requests to transfer to tertiary care. Further investigation into the elements we have described might provide insights into improvements in the quality of care at community hospitals that might reduce the rates of requests for transfer. Our results also highlight the importance of including patient or surrogate perspectives in evaluations of the appropriateness of care.