Researchers studying health care decision making generally focus on the interaction that unfolds between patients and health professionals. Using the example of allogeneic bone marrow transplant, in this article we identify decision making to be a relational process concurrently underpinned by patients' engagement with health professionals, their families, and broader social networks. We argue that the person undergoing a transplant simultaneously reconciles numerous social roles throughout treatment decision making, each of which encompasses a system of mutuality, reciprocity, and obligation. As individuals enter through the doorway of the consultation room and become "patients," they do not leave their roles as parents, spouses, and citizens outside in the hallway. Rather, these roles and their relational counterpoints--family members, friends, and colleagues--continue to sit alongside the patient role during clinical interactions. As such, the places that doctors and patients discuss diagnosis and treatment become "crowded rooms" of decision making.