There is a subclinical activation of coagulation and fibrinolysis system in lung cancer. Alterations in hemostatic system are seen frequently in lung cancer correlated with the prognosis of disease. In this prospective study, our purpose was to investigate the prognostic significance of hemostatic markers in patients with lung cancer. The study comprised 58 patients (22 squamous cell carcinoma, 16 adenocarcinoma, 20 small cell carcinoma). There were 55 men (95%)and 3 women (5%) with a mean age of 61 years range (36–74). Plasma level of platelets (PLT), prothrombin time (PT), active partial thromboplastin time (aPTT), antithrombin III (AT III), fibrinogen (F) and D-dimer level were measured before the initiation of any therapy. Patients were followed up for 17 (12–20) months. The median survival was determined as 6.4 months. Three histopathologic groups; squamous cell carcinoma, adenocarcinoma and small cell carcinoma were compared for the hemostatic parameters. There were no statistically significant differences among the histopathologic types for any of the parameters (P>0.05). Patients were divided into two groups as patients without distant metastasis (stages I,II,III) and with distant metastasis (stage IV). The group with distant metastasis had higher level of D-dimer than the other group (P<0.05). However, there were no statistically significant differences for D-dimer level between stages IIIB and IV (P>0.05). Patients having high D-dimer and low AT III level had poor survival in our study. Thus, high level of D-dimer and low AT III level were determined as correlated with short survival (P<0.05). These results suggest that elevated plasma level of D-dimer and low AT III level might be a sign of poor prognosis in patients with lung cancer.