Advance directive (AD) has been underutilized among patients with heart failure (HF). This study was performed to explore the ADs and examine factors associated with the completion of an AD survey in patients with HF. In a descriptive, correlational study, data on end-of-life values, treatment directives, and proxy (Korean-Advance Directive (K-AD) questionnaire) and factors associated with K-AD completion were collected among HF patients during outpatient visits. Of 67 patients (age, 67 years; male, 61.2%), 52.2% completed all or part of the K-AD. Among values, comfortable death was the most preferred (n = 15) followed by avoiding family burden (n = 6). In those completers, preferences for hospice care, cardiopulmonary resuscitation, ventilation support, and hemodialysis were 68.6%, 42.9%, 28.6%, and 28.6%, respectively. Female sex (odds ratio (OR) = 0.167), poorer HF prognosis (OR = 0.156), and better functional status (OR = 0.905) were associated with less likelihood of completing the AD survey. The findings suggest that in-depth AD discussion needs to be started earlier in patients with HF to facilitate completion of AD, especially in female patients. Future research should investigate if early discussion of ADs as part of advance care planning with integration into standard care of HF facilitates the documentation of ADs.