Purpose: As advanced medical care has resulted in the unintended consequence of prolonging deaths, there is a growing interest in the decision to withhold life-sustaining treatments. The purpose of this study was to determine factors associated with the decision to withhold life-sustaining treatments in middle-aged and older adults who die in hospital in the United States. Methods: This cross-sectional correlational study conducted secondary analysis of 2000-2012 exit interview data from the Health and Retirement Study. Adults aged 50 and older who died in hospital and who had made a decision regarding life-sustaining treatments were included. Multivariable logistic regression was used to identify factors related to the decision to withhold life-sustaining treatments. Results: Among 1,412 adults, the prevalence of the decision to withhold life-sustaining treatments was 61.1%. Significant factors associated with the decision to withhold life-sustaining treatments were being African American (Adjusted Odds Ratio [AOR]=0.50, 95% Confidential Interval [CI]=0.30~0.86), Catholic (AOR=0.5, 95% CI=0.32~0.93), having at least one private insurance policy (AOR=1.40, 95% CI=1.02~1.92), having a living will (AOR=1.71, 95% CI=1.04~2.83), and having discussed end-of-life care with someone (AOR=1.810, 95% CI=1.25~2.62). Conclusion: Differences in race and religious affiliation should be considered when older adults, family members, and health care providers make decisions regarding life-sustaining treatments at the end-of-life. Also, health insurance coverage for advance care planning makes it easier for people to discuss life-sustaining treatments with health care providers.