Conflicts between physicians and families about end-of-life decisions create challenging and emotionally difficult situations. In this article, we propose a "differential diagnosis" of such conflicts, distinguishing and describing the characteristics of families, physicians, and organizations and society that contribute to the "etiology" of the situation, as well as strategies for "diagnosing" the dominant factors. As a medical model, the differential diagnosis can be a useful tool to help physicians understand and manage conflicts about end-of-life care.