Palliative sedation (PS) is performed in the terminally ill patient to manage one or more refractory symptoms. Proportional PS, which means that drugs can be titrated to the minimum effective dose, is the form most widely used. From a quarter to a third of all terminally ill patients undergo PS, with a quarter of these requiring continuous deep sedation. The prevalence of PS varies according to the care setting and case mix. The most frequent refractory physical symptoms are delirium and dyspnea, but PS is also considered for existential suffering or psychological distress, which is an extremely difficult and delicate issue to deal with. Active consensus from the patient and advanced care planning is recommended for PS. The decision-making process concerning the continuation or withdrawal of other treatments is not the same as that used for PS. The practice differs totally from euthanasia in its intentions, procedures, and results. The most widely used drugs are midazolam and haloperidol for refractory delirium, but chlorpromazine and other neuroleptics are also effective. In conclusion, some patients experience refractory symptoms during the last hours or days of life and PS is a medical intervention aimed at managing this unbearable suffering. It does not have a detrimental effect on survival.