We retrospectively examined febrile (>38.3°C) adult patients with microbiologically confirmed coronavirus disease (COVID-19) (n=48) or influenza (n=63). The median pulse rate (/min)/body temperature (°C) ratio was significantly lower for COVID-19 patients (2.14; interquartile range, [IQR] 1.92–2.47) than for influenza patients (2.63; IQR, 2.31–2.93; P<0.0001). The area under the curve was 0.80 (95% confidence interval 0.71–0.88), optimal cut-off was 2.23, and sensitivity and specificity were 66.7% and 84.1%, respectively. Our preliminary results suggest that febrile patients with COVID-19 exhibit more severe bradycardia than those with influenza. Relative bradycardia is a useful feature for distinguishing COVID-19 from influenza.