Periodic and unexpected shortages of drugs, biologics, and even medical devices have become commonplace in the United States. When shortages occur, hospitals and clinics need to decide how to ration their available stock. When such situations arise, institutions can choose from several different allocation schemes, such as first-come, first-served, a lottery, or a more rational and calculated approach. While the first two approaches sound reasonable at first glance, there are a number of problems associated with them, including the inability to (...) make fine, individual patient-centered decisions. They also do not discriminate between what kinds of patients and what types of uses may be more deserving or reasonable than others. In this article I outline an ethically acceptable procedure for rationing drugs during a shortage in which demand outstrips supply. (shrink)