Purpose: This study explored the consistency between preferences for end-of-life care for elderly hospitalized patients and their primary caregivers and predictors of consistency. Patients and Methods: This cross-sectional correlational study recruited 100 dyads of elderly hospitalized patients and their primary caregivers from a medical center in Central Taiwan. A structural questionnaire about preferences for seven end-of-life medical treatment options involved cardiopulmonary resuscitation, intravenous therapy, nasogastric tube feeding, intensive care unit, blood transfusion, tracheotomy, and hemodialysis. Results: The consistency was 42.28% for preferences of end-of-life medical care between patients and caregivers. The Kappa values for seven life-sustaining medical treatments ranged from 0.001 to 0.155. Logistic regression showed that the predictors of consistency for preferences of treatment were: a patient with a signed living will (odds ratio [OR] = 6.20, p<0.01) and a male family caregiver (OR= 0.23, p<0.01) for cardiopulmonary resuscitation; a patient who visited relatives in the intensive care unit (OR= 2.94, p< 0.05) and a spouse caregiver (OR= 3.07, p< 0.05) for nasogastric tube feeding; a spouse caregiver (OR=3.12, p<0.05) and a caregiver who visited the intensive care unit (OR= 5.50, p<0.01) for tracheotomy; and a spouse caregiver (OR= 2.76, p<0.05) and a caregiver who visited the intensive care unit (OR= 4.42, p<0.05) for hemodialysis. Conclusion: End-of-life medical treatment preferences were inconsistent between patients and family caregivers, which might be influenced by Asian culture, the nature of the relationship and individual experiences. Implementation of advance care planning that respects the patient's autonomy and preferences about end-of-life care is recommended.