Aim: Activation of coagulation and fibrinolysis pathways is frequently associated with malignancy. The objective of our study was to detect D-dimer levels in lung cancer patients and to determine whether there is any relationship between the stage of cancer and survival. Method: From January 2005 to April 2007, sixty-five patients with histologically or cytologically confirmed lung cancer, treated at our institution were enrolled in the study. In each case, appropriate treatment modalities were recruited based on the clinical evaluation. Patients were followed up via phone calls to the patients themselves or their family members. Survival period was recorded as starting from the time of diagnosis to the date of death or termination of the study. Commercially available reagents were used to measure the levels of D-dimer. Result: There was no significant difference between histological types and tumor stages in terms of D-dimer levels. The plasma D-dimer levels in the alive patients were significantly lower than patients that died (p <0.05). High plasma D-dimer concentrations turned out to be a strong predictor of poor outcome (median survival period in patients with normal D-dimer levels was 426 days [95% CI, 275-576 days] vs. 179 days [95% CI, 68-289 days] in patients with increased D-dimer levels; log rank statistics, 7.05; p <0.05). Cox regression analyses showed that D-dimer (p <0.05) was a prognostic factor, independent of age and stage. Conclusion: We found that D-dimer was a prognostic factor, independent of age and disease stages