This Letter presents the findings of a cross-sectional study on the association between living with others and depressive symptoms among 1228 workers, aged 21-73 years, from a large hospital and its affiliated institute in Tokyo, 66.8% of whom had engaged in some sort of COVID-19-related work. The Introduction, Methods, Results, Discussion, and Tables are presented as an online supplement (Appendix S1). The COVID-19 pandemic is having a particularly significant psychological impact on health-care workers, with 25% reported to be depressed during the pandemic. 1 Health-care workers are not only at higher risk of exposure to SARS-CoV-2 and increased workloads, 2 but also social isolation and rejection due to the high probability that they will come into contact with potentially infectious COVID-19 patients. 3 Social support has been recognized as a protective factor for mental health among health-care workers during the COVID-19 pandemic. 4 However, social restrictions lead to reduced access to support from family and friends, and degrade social support systems, which can cause loneliness and depressed mood. 5 In particular, individuals who live alone may be at high risk of adverse psychological conditions when they miss out on opportunities for emotional exchange and social support with cohabitants. These findings indicate the need to explore the relation between living alone and depressive symptoms during pandemic-related restrictions. While accumulating evidence suggests that living alone exacerbates depressive symptoms, 6 research on this issue among health-care workers during the COVID-19 pandemic is scarce. To our knowledge, only one recent study in China has investigated the relation between living alone and depression symptoms in medical staff during the COVID-19 pandemic. 7 The aim of this study was to examine the cross-sectional association of living with others with depressive symptoms among staff members at the National Center for Global Health and Medicine (NCGM) in Tokyo, Japan, a leading institute in the response to COVID-19 in Japan. Data for the present study were derived from the NCGM Clinical Epidemiology Study on SARS-CoV-2 Antibody, an ongoing clinical epidemiological study conducted among workers at NCGM. The first wave of the survey, conducted in July 2020, mainly targeted those who had