To clarify the prevalence and the characteristics of patients who received palliative sedation therapy for psycho-existential suffering, a questionnaire was sent to 105 responsible physicians at all certified palliative care units in Japan. The participants were requested to report the number of patients who received continuous deep sedation for refractory psycho-existential suffering during the past year, and to provide details of the 2 most recent patients. A total of 81 physicians returned questionnaires (response rate, 80%). Twenty-nine physicians (36%) reported clinical experience in continuous deep sedation for psycho-existential suffering. The overall prevalence of continuous deep sedation was calculated as 1.0% (90 cases/8,661 total patient deaths), and a total of 46 patient histories were collected. Performance status just before sedation was 3 or 4 in 96%, and predicted survival was 3 weeks or less in 94%. The suffering requiring sedation was feeling of meaninglessness/worthlessness (61%), burden on others/dependency/inability to take care of oneself (48%), death anxiety/fear/panic (33%), wish to control the time of death by oneself (24%), and isolation/lack of social support (22%). Before sedation, intermittent sedation and specialized psychiatric, psychological, and/or religious care had been performed in 94% and 59%, respectively; 89% of 26 depressed patients had received antidepressant medications. All competent patients (n=37) expressed explicit requests for sedation, and family consent was obtained in all cases where family members were available (n=45). Palliative sedation for psycho-existential suffering was performed in exceptional cases in specialized palliative care units in Japan. The patient condition was generally very poor, and the suffering was refractory to intermittent sedation and specialized psychiatric, psychological, and/or religious care. Sedation was performed on the basis of patient and family consent. These findings suggest that palliative sedation for psycho-existential suffering could be ethically permissible in exceptional cases if the proportionality and autonomy principle is applied. More discussion about the role of palliative sedation therapy for refractory psycho-existential suffering in end-of-life care is urgently necessary.