Tissue factor (TF) is the physiological initiator of blood coagulation. It has been suggested that TF also regulates tumor growth and angiogenesis. We therefore used immunohistochemistry to analyze the expression of TF and angiogenesis in non-small-cell lung carcinomas of 191 patients. A significant association was found between TF expression and microvessel density (MVD): TF-negative carcinomas more frequently exhibited low MVD. Additionally, a significant relationship between TF expression and the expression of vascular endothelial growth factor (VEGF) was discovered. TF was also compared with the resistance of the carcinomas to doxorubicin, as measured in vitro: TF-negative tumors were more frequently resistant to doxorubicin than were TF-positive tumors. Kaplan-Meier survival analysis revealed that survival times were longer in patients with TF-negative tumors than in patients with TF-positive tumors. These data suggest that TF functions as an additional angiogenic factor that could be used as a new prognostic and predictive factor for non-small-cell lung carcinomas.