Each year in the United States, individuals who lack decision-making capacity because of acute or chronic cognitive impairment are in situations in which important medical decisions must be made for them, but tens of thousands of these individuals have no known family members or designated surrogates available to help with those decisions. Such individuals constitute 16% of patients in intensive care units, 3% of nursing home residents, and a large but unspecified number of individuals in a variety of settings who are facing end-of-life decisions. Several approaches are currently used to aid in medical decision-making for people without families or designated surrogates, including hospital ethics committees, court-appointed surrogate agents, reliance on advance directives if they are available, and even the use of computer-based decision systems. These approaches all have limitations and often result in individuals receiving care that would not have been their preference. Additionally, because clinical care teams must wrestle with uncertainty about best approaches to care, lengths of hospital stay for individuals without family are longer, resulting in higher healthcare costs and potentially more-aggressive interventions than individuals with family experience. This article reviews medical decision-making for older adults without families or designated surrogates and proposes a solution: “health fiduciaries”—a new type of professional trained and certified to act as a surrogate decision-maker for individuals who are unable to make decisions for themselves.