This essay surveys the need for a clear and objective definition of medical futility. It is urged that once agreement is obtained for structuring operational guidelines for determining futility, a three-tier decisional structure can be developed for testing whether a given treatment falls within the scope of these guidelines. Under the first tier, the treating physician would be given the primary responsibility for making the determination to withhold treatment on the grounds of futility. While the physician would be under a duty not to prescribe treatment deemed futile, he would be obliged to inform the patient and his family of this decision, including the reasons for it, in order to allow, under the second tier, for an appeal to be taken by the patient or family to the hospital ethics committee. The third tier recognizes a right of limited appeal to the courts.