Aim: Pentraxin 3 (Ptx3) is a new biomarker in inflammatory disorders and thromboembolic events. Several studies showed elevated levels of Ptx3 in acute coronary syndrome, infectious diseases, and malignancies. In our study, we aimed to evaluate the relationship between Well's Score and Ptx 3 levels in Pulmonary embolism (PE) patients for determining the probability and severity of the disease. Material and Method: Twenty-two PE patients diagnosed with CT angiography presented to our emergency department and 20 healthy adults as a control group were enrolled in the study. Age, gender, Ptx3. CRP, D-dimer levels and Well's Scores of the patients were noted. After one month, Ptx3, CRP and quantitative D-Dimer levels of the patients were tested again. Results: Mean 1st Ptx3 level of the PE group was higher than the 2nd Ptx3 level and the Ptx3 level of the control group. In the PE group, mean 1st Ptx3 level of the females was 1.87 +/- 0.48 and 2.37 +/- 0.96 in males and was not significantly different. The 1st Ptx3 levels and the 2nd Ptx3 levels of the PE groups were significantly different (p..0.001). The 1st Ptx3 levels of the PE group and the Ptx3 levels of the control group were significantly different (p=0.001). The 2nd Ptx3 level of the PE group and Ptx3 levels of the control group were significantly different (p=0.001). In the PE group, 1st Ptx3 levels were significantly related with Well's Score of the patients (p=0.001). Discussion: Ptx3 is an important inflammatory marker and secreted from a wide range of cells Including adipocytes, cardiomyocytes, brain cell, endothelial cells, and alveolar epithelial cells and may be helpful in determining the probability of PE in suspicious patients in the emergency department.