We analysed a cohort of patients with normotensive pulmonary embolism (PE) in order to assess whether combining echocardiography and biomarkers with the pulmonary embolism severity index (PESI) improves the risk stratification in comparison to the PESI alone. The PESI was calculated in normotensive patients with PE who also underwent echocardiography and assays of cardiac troponin I and brain natriuretic peptide. 30-day adverse outcome was defined as death, recurrent PE or shock. 529 patients were included, 25 (4.7%, 95% CI 3.2-6.9%) had at least one outcome event. The proportion of patients with adverse events increased from 2.1% in PESI class I-II to 8.4% in PESI class III-IV, and to 14.3% in PESI class V (p<0.001). In PESI class I-II, the rate of outcome events was significantly higher in patients with abnormal values of biomarkers or right ventricular dilatation. In multivariate analysis, the PESI (class III-IV versus I-II, OR 3.1, 95% CI 1.2-8.3; class V versus I-II, OR 5.5, 95% CI 1.5-25.5 and echocardiography (right ventricular/left ventricular ratio, OR (for an increase of 0.1) 1.3, 95% CI 1.1-1.5) were independent predictors of an adverse outcome. In patients with normotensive PE, biomarkers and echocardiography provided additional prognostic information to the PESI.