Aim To observe whether lipid peroxidation injury to endothelial cells (EC) induces intercellular adhesion molecule 1(ICAM 1) expression. Methods The lipid peroxidation injury to cultured human umbilical vein endothelial cells (hUVEC) was induced by exposure of the cells to diamide either at a same concentration for different incubation time or at different concentrations, but for a same incubation times. The ICAM 1 mRNA expression in hUVEC was determined by reverse transcriptase polymerase chain reaction (RT PCR), and was normalized with β actin mRNA. The ICAM 1 protein expression in hUVEC was determined by cell enzyme linked immunosorbent essy (ELISA). Results RT PCR showed that the ratios of the absorbance (A) values of ICAM 1 mRNA to that of the β actin mRNA expressed in hUVEC exposed to diamide at different concentrations (1 μmol/L, 5 μmol/L and 10 μmol/L) for 8 h was 0.535, 0.908 and 1.186, respectively. Whereas the ratio of the A values of ICAM 1 mRNA to that of the β actin mRNA expressed in hUVEC exposed to diamide at a concentration of 5 μmol/L for 0, 4 h and 24 h was 0.185, 0.598 and 1.292, respectively. Cell ELISA showed that the A values of ICAM 1 protein expressed in hUVEC exposed to diamide at different concentrations (1 μmol/L, 5 μmol/L and 10 μmol/L) for 4 h were 0.1387, 0.1775 and 0.2326, which were 1.34 fold, 1.71 fold and 2.25 fold as much as that of the control group (0.1035), respectively. There was a significant statistical difference between groups (F=38.89, p<0.01). Taken together, these results suggest that ICAM 1 expression in hUVEC induced by diamide was in a dose and time dependent manner. Conclusions Lipid peroxidation injury to EC induced by diamide may up regulate ICAM 1 mRNA and protein expression, which play an important role in the recruitment of monocytes into subendothelial space in atherogenesis.