In a statement published in this issue, the Public Policy Committee of the American Geriatrics Society endorses the view that chronological age should not be a criterion for exclusion of individuals from medical care. This article aims to amplify the Committee's position by placing it within a broader context and identifying its justification in ethical argument. The paper is divided into three parts. The first part clarifies the difference between allocation (the distribution of funds between categories) and rationing (the distribution of funds within a single category). It is argued that given the current allocation of funds to medical care, some form of rationing is unavoidable. As others have noted, rationing is already occurring in an informal and piecemeal fashion. However, ethically sound rationing requires publicly debated and defensible policies. The second section of the paper reviews a number of arguments advanced in favor of rationing medical care on the basis of age. Objections to these arguments are carefully set out. The final part of the paper details and defends a series of positive arguments establishing special duties to the elderly. The paper concludes that to the extent that scarcity forces rationing, older persons should not be excluded because they are old.