The “Act on Life-Sustaining Treatment Determination” was passed in Korea in 2016 and will take effect after the enactment of certain ordinances and rules. In this study, we analyzed the decision-making process regarding the withholding and withdrawal of life-sustaining treatment in four countries: Taiwan, Japan, the US, and the UK. Each country introduced advance directives either through legal forms (Taiwan, the US), limited legal forms (the UK), or arbitrary forms (Japan). Japan takes a guideline-centered approach, whereas Taiwan takes law-centered approach. And while a patient’s will about life-sustaining treatment (LST) is respected as part of a patient’s self-determination in the US, physicians can refuse treatment if its benefits are extremely uncertain. On the other hand, in the UK, if a patient has lost decision-making capacity, physicians can make decision regarding the patient’s best interests. In this article, it is argued that minimal standards should be established in Korea to prevent possible abuse as well as to respect patients’ right to self-determination; however, it is desirable to support good decision-making processes between physicians and patients (and their family members) rather than to over-regulate current practice.