【Abstract】 Objective To improve the knowledge of pulmonary embolism with normal D-dimer levels. Methods Nine consecutive patients of established pulmonary embolism with a normal D-dimer concentration admitted from January 2004 to December 2009 were analyzed retrospectively. Results Pulmonary embolism was confirmed in the 9 patients with a normal D-dimer concentration. Pulmonary embolismwas confirmed in only one patientwith an unlikely probability of pulmonary embolism. Wells score was 3 and the localization of the emboli was segmental emboli. In other 8 patients with a likely clinical probability of pulmonary embolism, the complaints of those patients existed between 1 hour and 2 months.Wells score was between 4. 5 and 7. 5, with a median of 6. 0. D-dimer concentration was between 0. 1 and 0. 5 mg/L, with a median of 0. 3 mg/L. The localization of the emboli was sub-segmental emboli in 3 cases,segmental emboli in 4 cases, and central emboli in 2 cases. Conclusions Our findings indicate that it is essential to examine the patient and assess the clinical probability at the first, then the D-dimer concentration should be taken into account. In patients with a likely clinical probability, a normal D-dimer test result can not exclude pulmonary embolism, and additional imaging testing is necessary.