Because most patients are decisionally incapacitated at the end of life, health care providers often rely on advance directives or proxies’ substituted judgment for guidance in treatment decisions. In a survey of 202 older adults and their respective proxies, we compared older adults who would reject life-sustaining care to those who would accept it in terms of the availability and accuracy of the information sources that providers would consult, viz., whether the patient had (a) completed a living will, (b) designated a durable power of attorney for health care (DPAHC), and (c) discussed wishes with a proxy; and (d) we calculated the accuracy of proxies’ substituted judgment. Older adults who would accept all treatments were significantly less likely to have completed a living will, assigned a DPAHC, or discussed their wishes with their proxies, and their proxies were much less accurate in understanding their wishes.