Purpose <p>To identify the postoperative mortality in patients requiring home oxygen therapy (HOT).</p> Methods <p>This descriptive study used a nationwide hospital-based database constructed by JMDC Inc. (Tokyo, Japan). Patients aged ≥ 18&#xa0;years requiring HOT who underwent surgery between January 2014 and June 2022 were included. The study outcomes were in-hospital and 30-day postoperative mortality rates and other complications. We established a non-HOT group matched by age, sex, procedure, and surgical urgency for contrast and analyzed mortality in subgroups based on the reason for HOT, surgical department, and urgency.</p> Results <p>Among the 3349 patients receiving HOT who underwent surgery, 293 (8.7%) in-hospital mortalities and 213 (6.4%) 30-day mortalities were reported. Postoperative pulmonary complications were observed in 359 (10.7%) patients, and 227 (6.8%) had non-respiratory complications. Furthermore, 123 (3.7%) in-hospital mortalities and 74 (2.2%) 30-day mortalities were also reported in the non-HOT group (3323 patients). The subgroup analysis indicated no significant differences in mortality or complications based on the reason for HOT. Higher mortality rates were reported in gastroenterology (9.3%), dermatology (14.7%), respiratory (11.8%), otolaryngology (36.5%), and neurosurgery (16.3%) departments. In-hospital and 30-day mortalities for emergency surgeries in the HOT group were 17.3 and 13.4%, respectively.</p> Conclusion <p>Among patients requiring HOT, in-hospital and 30-day mortalities were 8.7 and 6.4%, respectively. In addition, emergency surgeries may contribute to higher postoperative mortalities. Future research should identify specific mortality risk factors and develop perioperative management strategies to reduce these risks.</p>