OBJECTIVE To investigate the present status of anxiety among nurses fighting the spread of COVID-19 and its association with perceived stress and insomnia. BACKGROUND With the outbreak of COVID-19, nurses have been caring for infected patients for a considerable length of time in Wuhan, China. Previous COVID-19 studies generally focused on patients' medical treatment, but few considered healthcare workers' psychological needs while working with a pandemic involving an unfamiliar infectious disease. Numerous nurses have experienced mental health problems, such as anxiety. METHODS The STROBE guidelines for a cross-sectional questionnaire were implemented. METHODS An online survey of 643 frontline nurses working with COVID-19-infected patients was conducted from 3-10 March 2020. Sociodemographic data were collected, and the Generalized Anxiety Disorder Scale, the Chinese Perceived Stress Scale and the Athens Insomnia Scale were administered. RESULTS One-third (33.4%) of participants reported anxiety, which was associated with perceived stress and insomnia among Chinese frontline nurses in Wuhan during the COVID-19 pandemic. Significant associations were found between anxiety, perceived stress, insomnia, working four-night shifts per week, experience working during more than two epidemics and fear of COVID-19. CONCLUSIONS This study found that a substantial proportion of frontline nurses caring for COVID-19-infected patients experienced anxiety. We recommend that nurse managers focus on working conditions and cultivate safe and satisfactory work environments. Meanwhile, frontline nurses should foster awareness of mental health and rely on online resources for psychological training to alleviate anxiety. CONCLUSIONS The findings of this study could facilitate better understanding of anxiety among frontline nurses; more importantly, healthcare authorities and nursing managers need to pay more attention to ensuring intervention training to reduce anxiety for frontline nurses worldwide.