Purpose: The purpose of this study was to identify factors influencing nurses’ performance of care in COVID-19 wards. Methods: The participants were 132 nurses who worked in COVID-19 wards at three hospitals, and were recruited from April 1 to May 31, 2021. Data were analyzed using descriptive statistics, t-test, ANOVA, and multiple regression analysis with SPSS/WIN 24.0 program. Results: Nursing performance was significantly and positively correlated with ethical sensitivity (r = .75, p < .001), nursing professionalism (r = .67, p < .001), and social support (r = .67, p < .001). Nursing professionalism was positively correlated with ethical sensitivity (r = .64, p < .001) and social support (r = .55, p < .001). Multiple regression analysis for nursing performance revealed that the most significant factor was ethical sensitivity (β = .47, p < .001). Ethical sensitivity, nursing professionalism, and social support explained 66.0% of total variance in nursing performance. Conclusion: Ethical sensitiviy, nursing professionalism, and social support significantly influence nurses’ performace of care in COVID-19 wards. It suggests that intervention programs should be directed at improving nurses’ ethical sensitivity, bolstering social support, and enhancing nursing professionalism.