Aim To well understand the role of oxidized low density lipoprotein (ox-LDL) in the pathogenesis of thrombotic complications in atherogenesis. Methods LDL was isolated from normal heparinized blood by density gradient ultracentrifugation and oxidized by CuCl 2. Total RNA was extracted from human umbilical vein endothelial cells (hUVECs) exposed to LDL or ox LDL by guanidinium isothiocyanate method. The quantification of tissue factor pathway inhibitor (TFPI) mRNA in hUVECs was carried out by reverse transcriptase PCR (RT PCR). Results hUVECs were able to express TFPI mRNA constitutively. The expression was not affected by LDL but effectively inhibited by ox LDL in a time and dose dependent manner. Conclusions Oxidized LDL may play an important role in inducing coagulation in atherosclerotic lesion by inhibition of expression of TFPI in vascular endothelial cells.