The aims of this study were to compare the clinical features of patients with pulmonary embolism (PE) and patients in whom the initial suspected diagnosis was not confirmed by the complementary studies and to determine the possible clinical differences among patients with PE according to age. A retrospective review of the charts of a group of patients with PE (n, 96) and another without PE (n, 96) was carried out. The patients with PE over 65 years of age (n, 64) were compared with those under 66 years of age (n, 32). The variables related to PE were absence of known heart disease, duration of symptoms </=2 days, pleuritic chest pain, absence of cough, pCO(2) <4.8 kPa (36 mmHg), and normal chest X-ray. The variables associated with the existence of PE in patients over 65 years of age, when contrasted with younger patients, were female sex, absence of pleuritic chest pain, abnormal chest X-ray, hypoxemia (pO(2) < 8.7 kPa (65 mmHg) and absence of S1Q3T3 pattern in ECG.The duration of symptoms and the presence of hypocapnia, pleuritic chest pain, and normal chest X-ray may lead to the suspicion of PE. Pleuritic pain and S1Q3T3 pattern are less commonly found in old patients with PE.