The clinical diagnosis is not reliable in pulmonary thromboembolism (PTE) because the symptoms are mostly nonspecific. Different clinical prediction rules for PTE have been described recently. These rules are used to aid clinicians in assigning a pre-test probability to patients with clinical signs and symptoms of disease. The aim of this study was to assess the clinical probability of PTE using three different models (Wells, Wicki and modified Hyers scores) and to find their power to determine PTE probability. Clinical probabilities of patients with PTE were determined with Wells, Wicki and modified Hyers scores. Cramer's, contingency coefficient (CC), Spearman's rho, Kendal's tau-b and kappa tests were used for statistical analysis. The study included 248 patients (119 male, 129 female; mean age = 57 +/- 16.7 years). Although 61.3% of the patients were assigned high clinical probability with modified Hyers score, 56% and 50% of them were assigned moderate clinical probability with Wicki and Wells scores, respectively. The correlations of the clinical probabilities was low according to kappa correlation test and moderate according to the Cramer's, CC, Spearman's rho and Kendal's tau-b tests among these three scores. In conclusion, modified Hyers score showed higher percentage of high probability compared to Wells and Wicki scoring systems and the best correlation was found between the modified Hyers and Wells scores.