The objective of this pilot study was to examine factors associated with the completion of advance directives (ADs) among patients with hematologic disorders in Korea. Using a descriptive design, patients with largely hematologic malignancies completed the questionnaires, including the Korean–Advance Directive (K-AD) model, which pertains to values, treatment wishes, and proxy appointment. Of 45 patients (aged 48.7 ± 10.7 years, 51.1% men), two-thirds had leukemia (40.0%) and lymphoma (26.7%). “Dying comfortably” was the most frequently selected value (n = 20). Regarding treatment wishes, hospice care was the most desired type (n = 22), whereas aggressive treatments, such as cardiopulmonary resuscitation, were less preferred (n = 3). The patient’s spouse was most frequently appointed as a proxy (n = 27). Patients who completed all the 3 components of the K-AD model (51.1%) were less depressed (t = −2.31; P = .028) and more likely to perceive the benefits of the K-AD model (t = 2.07; P = .045), compared with the noncompleters (48.9%). Further, being male (odds ratio [OR], 6.42; P = .031), having higher scores on depressive symptoms (OR, 1.28; P = .016), and perceived barriers (OR, 1.08; P = .040) were associated with lower tendency to complete the K-AD model. These findings support the need for earlier introduction of ADs in hematologic disorders, with consideration of modifiable factors such as depression or barriers to end-of-life care decisions.