Background: The National Early Warning Scores (NEWS) easily and objectively measures acute clinical deterioration. However, the performance of NEWS to predict mortality in patients with acute pulmonary embolism (APE) is still required. Therefore, the objective of this study was to evaluate the performance of the NEWS in predicting the mortality of patients with APE. Methods: NEWS and Pulmonary Embolism Severity Index (PESI) at diagnosis time were calculated. Risk regression analysis was performed to identify the NEWS and PESI risk classification as a predictor for 30 days all-cause mortality and PE-related mortality. Results: NEWS was significantly higher in non-survivors compared to survivors (median (IQR) was 10 (7, 11) vs. 7 (2, 9), respectively, p < 0.001). The best cut-off point of NEWS in discriminating APE patients who non-survived from those who survived at 30 days was ≥9, with a sensitivity and specificity of 66.9% and 66.3%, respectively. The adjusted risk ratio of 30-day all-cause mortality in patients with initial NEWS ≥ 9 was 2.96 (95% CI; 2.13, 4.12, p < 0.001). Conclusions: The NEWS can be used for mortality prediction in patients with APE. APE patients with NEWS ≥ 9 are associated with a high risk of mortality and should be closely monitored.