Background: Little is known about the role of advance directives (AD) in end-of-life (EOL) care for adolescents and young adults (AYA) undergoing hematopoietic stem cell transplant (HSCT). Objective: The study objective was to describe the frequency, type, and influence of AD on the use of lifesustaining treatment (LST) in AYA patients undergoing HSCT. Methods: We performed a retrospective chart review of 96 patients aged 14-26 undergoing HSCT between April 2011 and January 2015 at the University of Minnesota. LST was defined as the use of positive pressure ventilation (PPV), dialysis, or CPR. Results: Of the 96 patients, survival was 72.9%, and 23% had an AD. Of the 26 patients who died, 13 (50%) had an AD. Among the 19 patients who died in the ICU, there was no significant difference in PPV, dialysis, withholding or withdrawing of LST, or timing of do not resuscitate (DNR) orders between those with ADs preferring LST (n = 5), those naming proxies only (n = 4), and those without ADs (n = 10). Patients with ADs expressing preference for LST were significantly more likely to receive CPR than those with proxies or those without ADs ( p = 0.02). Conclusion: A minority of AYA patients undergoing HSCT had ADs. Patients received care that was strongly associated with their preferences. With the exception of CPR, the use of LST did not differ between those with ADs and those without.