Although palliative sedation (PS) is a common practice in the palliative care of cancer patients in Western countries, there is little related research on the practice in Korea. PS can be classified into several categories according to sedation level and continuity. PS is clearly distinct from euthanasia. While euthanasia is illegal and regarded as unethical in Korea, there is little ethical and legal controversy about PS in terms of the doctrine of double effect. Most studies have asserted that PS does not shorten the survival of terminal cancer patients. Since preference for PS heavily depends on stakeholder value, it should be preceded by shared decision-making through full communication among the patient, family members, and medical team. This is a narrative review article analyzing previous studies, especially from the three Eastern Asian countries, Korea, Japan and Taiwan, which share similar cultures compared with Western countries. Practical issues concerning PS—for example, prevalence, type and dosage of medications, salvage medication, timing of its initiation, and assessment—are described in detail.