OBJECTIVE The authors explore the possibility that psychiatrists inappropriately extend their views on suicide by the medically well to refusal of lifesaving treatment by the seriously medically ill. METHODS The legal and bioethics literature on competence to refuse lifesaving treatment and the possible impact of depression on this refusal is reviewed. RESULTS Over the past 20 years, the burden of proof concerning the mental competence of seriously medically ill patients who refuse lifesaving treatment has shifted to the persons who seek to override these refusals. However, in psychiatry a patient's desire to die is generally considered to be evidence of an impaired capacity to make decisions about lifesaving treatment. This contrast between ethical traditions is brought into clinical focus during the evaluation and treatment of medically ill patients with depression who refuse lifesaving treatment. The clinical evaluation of the effect of depression on a patient's capacity to make medical decisions is difficult for several reasons: 1) depression is easily seen as a "reasonable" response to serious medical illness, 2) depression produces more subtle distortions of decision making than delirium or psychosis (i.e., preserving the understanding of medical facts while impairing the appreciation of their personal importance), and 3) a diagnosis of major depression is neither necessary nor sufficient for determining that the patient's medical decision making is impaired. CONCLUSIONS Depression can be diagnosed and treated in patients with serious medical illness. But after optimizing medical and psychiatric treatment and determining that the patient is competent to make medical decisions, it may be appropriate to honor the patient's desire to die.