Objectives The aim of the study is to find how concomitant deep venous thrombosis (DVT) changes the clinical course of pulmonary embolism. Methods Three hundred and five patients with pulmonary embolism were examined and grouped into DVT and non-DVT groups. Both groups were compared with regard to demography, predisposing factors, clinical signs, thrombotic burden, and one-month mortality rate. Results The patients with DVT had a more severe clinical presentation: higher heart rate (94.80 ± 18.66 beats per minute versus 87.9 ± 13.90 in the non-DVT group, p = 0.00033), more hemodynamic instability (11.35% versus 3.05% in the non-DVT group, p = 0.005), and less pCO2 in arterial blood gases (30.81 ± 7.94 mmHg versus 32.59 ± 7.35 mmHg in the non-DVT group, p = 0.049). The DVT group had heavier thrombotic burden in pulmonary artery, measured by Mastora score. The one-month mortality rate did not differ statistically between groups. Conclusions Patients with symptomatic pulmonary embolism and concomitant DVT have heavier thrombotic burden in the pulmonary artery and more severe clinical presentation compared to those without DVT, but a similar one-month mortality rate.