Objective:To investigate the clinical features of pulmonary thromboembolism in patients with primary lung cancer in relation to thoracotomy, and to shed light on prevention, diagnosis and treatment of this fatal disease after lung resection. Methods: A total of 1245 cases with primary lung cancer received thoracotomy in the past 13 years were retrospectively reviewed. Clinical data of a total of 14 patients (1.1%) suffering from pulmonary thromboembolism and requiring cardiao-pulmonary resuscitation were collected and analyzed. Results: The diagnosis was established primarily by clinical findings in 9 cases (64.3%), including further confirmation of one case during operation, by pulmonary ventilation-perfusion scan in 2, by spiral CT angiography in 1, by pulmonary angiography in 1, and by autopsy in 1 case. Even using prompt resuscitation, 8 patients (57.1%) died within 48 h (mean 4 h) after the onset of the symptoms. Six cases eventually recovered. Of the 6 salvaged patients, they all received anticoagulation therapy with heparin intravenously and warfarin orally, including 3 cases of additional thrombolytic therapy with urokinase. Two cases with massive pulmonary emboli received emergency surgery, including one pulmonary embolectomy, and one bilobectomy after right upper lobectomy, with satisfactory results. Conclusion: Massive pulmonary embolism is an infrequent but fatal early postoperative complication after lung resection. The diagnosis should be based mainly on clinical findings in order to initiate the appropriate therapy immediately. The direct diagnostic techniques including radionuclide pulmonary scan, spiral CT angiography, and pulmonary angiography could be based on a careful evaluation of the expected benefits and risks of the various available treatments.