BACKGROUND Pulmonary embolism (PE) is known as one of the major causes of cardiovascular morbidity and mortality. Identification of high risk patients for short term and long-term mortality is crucial. The purpose of this study is to demonstrate the prognostic importance of simplified pulmonary embolism severity index (sPESI), radiological investigations and comorbidities in terms of short-term mortality by simultaneous assessment of sPESI score, pulmonary computed tomography (CT) angiography findings and underlying comorbidities in patients diagnosed with acute pulmonary embolism. METHODS We retrospectively evaluated 570 patients diagnosed with acute PE confirmed by computer tomography pulmonary angiography (CTPA). Comorbidities were recorded, pulmonary embolism severity index scores were calculated and CTPA data were evaluated as predictors for short-term mortality. RESULTS The study population consisted of 570 patients, 292 (51.2%) patients were female and 74 patients (12.9%) died within 30 days due to PE diagnosis. In univariate analysis male gender (p= 0.031), congestive heart failure (CHF)(p< 0.029), main pulmonary artery involvement (p= 0.045), presence of pleural effusion (p= 0.001) and pericardial effusion (p= 0.004) at time of diagnosis and high risk sPESI group (p< 0.001) had a significant influence on mortality. In the multivariate analysis, pleural effusions (HR, 1.67; CI, 1.05-2.66; p< 0.030) and sPESI high risk group (HR, 9.56; CI, 4.71-19.43; p< 0.001) were remained significant and independent prognostic factors for survival. CONCLUSIONS The present study underlined that presence of pleural effusion at the time of diagnosis in patients with massive pulmonary embolism and a high sPESI score in other patients were significant predictors of short-term mortality.