As part of an effort to look at “what differences make a difference” for bioethicists interested in clinical decisionmaking, Erik Parens, the editor of this special section, asked us to look at social class. When we began our research for this paper, we were surprised to find that although bioethicists have written much on social class and such macrolevel issues as access to healthcare and the distribution of scarce resources, and have paid some attention to the effects of class on patient-provider relationships, bioethicists have written little specifically that looks at the implications of social class for medical decisions in individual cases.