ICU clinicians commonly make decisions that allocate resources. Because of the high cost of ICU care, these practitioners can expect to be involved in the growing dilemma of trying to meet increasing demand for healthcare services within financial constraints. In order to participate meaningfully in a societal discussion over fairness in allocating scare and expensive resources, ICU practitioners should have more than a superficial knowledge of the principles of distributive justice. Distributive justice refers to fairness in the distribution of limited resources and benefits. Fairness refers to giving equal treatment to all those who are the same with regard to certain morally significant characteristics and treating in a different manner those who are not the same. Although theoretical issues remain unresolved as to which characteristics should be most significant, the United States has a strong cultural value that regards individuals as inherently valuable and having equal social worth. From this, it is likely that only an egalitarian approach to allocation of lifesaving healthcare resources will be acceptable. Studies of how ICU resources have been allocated during times of scarcity indicates that, in general, when beds are scarce, the average severity of illness of those admitted to the ICU increases. However, in some hospitals, political and economic factors appear to play important roles in determining who has access to scarce ICU beds. Of great concern is documentation of a widespread pattern in which fewer hospital resources, including ICU resources, are provided to seriously ill patients of minority status or with low levels of insurance reimbursement. How society's values get translated into allocation decisions is another unresolved issue. One recent example of how this occurred is the Oregon Medicaid Plan. This plan extended Medicaid coverage to additional people in poverty, despite the same amount of state and federal funds. This was accomplished by not reimbursing what were regarded as marginally beneficial services on the basis of medical and community input. Portents of how society might be involved in the future of health care are illustrated by the argument that society should limit access to all therapies except palliative care solely on the basis of advanced age. Until an open consensus develops in U.S. society about how to allocate scarce healthcare resources, the delivery of ICU care will continue to be at risk of covert, de facto rationing based on ability to pay, race, or other nonmedical personal characteristics.