What ethical considerations are made in decisions on distribution of scarce health care resources? Are the distributional decisions consciously based on explicit ethical principles, and if so, what principles? Both theoretical and political arguments on distribution of scarce medical resources frequently make simultaneous considerations of costs, probability of positive effects of medical treatment, and ethical values, possibly sacrificing explicit formulation of the ethical problem (or each element in general). To explicate the normative problem, it is convenient to distinguish between the three parts. A model of elements in the decision problem is presented. These elements are: Costs (C), probability of positive effect of treatment (P), and the (ethical) values related to the treatment of an individual (V). Stipulation of values on C, P, and V, respectively, is further discussed; ethical considerations (V) are the primary focus. Arguments for specific distributional principles are distinguished depending on whether the basis is P, V or C.