Abstract Background It is currently unknown how widespread is the practice of palliative care in intensive care units (ICUs) in Japan. This study aimed to determine evaluate the delivery and self-reported practice of palliative care in ICUs in Japan. Methods A self-administered questionnaire was sent to the physician directors of all 873 ICUs in Japan in August 2020. Results Of the 873 institutions, 439 responded the questionnaire (response rate: 50%) and 413 responses were included in the analysis. The responding physicians thought palliative care was appropriate for physical symptoms (36%, 95% Confidence Interval [CI] 32–41), the provision of information (32%, 95% CI: 28–37), psychological distress (25%, 95% CI: 21–29) and in Post Intensive Care Syndrome (PICS) prevention (20%, 95% CI: 17–24). Only 4% (95% CI: 2–6) of participants indicated that they always provided palliative care screening for the patients admitted to the ICU. The most common method to determine eligibility for palliative care was the “prediction of prognosis by clinician’s experience” (54%, 95% CI: 50–59). Thirty-one percent (95% CI: 27–36) of participants responded that there was no clear method used to decide which patients need palliative care. Fifty-four percent of the participants answered they had no standardized protocols for symptom management at all. Less than 5% answered they had standardized protocols for end-of-life symptom management or terminal weaning off mechanical ventilation including extubation of endotracheal tubes. Conclusions In Japan, the dissemination of palliative care and its integration into ICU care appears insufficient. To improve the quality of life of patients who are admitted to ICU, it may be useful to implement palliative care screening and multidisciplinary conferences, to develop standardized protocols for symptom management and withholding or withdrawing of life-sustaining treatment, and to educate primary palliative care for all ICU physicians.