Aim To understand whether native very low density lipoprotein (n VLDL) and oxidized very low density lipoprotein (ox VLDL) induce the cultured human umbilical endothelial cells (EC) to express macrophage inflammatory protein 1α (MIP 1α). Methods The EC were cultured in serum free medium containing 80 mg/L of n VLDL and ox VLDL respectively, while the control group without lipoproteins. After 24 h incubation, the EC grown on the cover slips were fixed and in situ hybridized with the Digoxigenin labeled MIP 1α cDNA probe. The MIP 1α mRNA expressed by the cells of every group was determined by reverse transcription polymerase chain reaction (RT PCR) as well. The MIP 1α protein expressed by the cells was detected by immunocytochemistry. Results Densitometry scan showed that the cultured EC could express MIP 1α mRNA, and the integral absorbance (A) values of the cells exposed to lipoproteins in situ hybridized with the probe metioned above were significantly higher than that of the control group. Analysis of variance demonstrated that there was significant difference among groups (p<0.01). RT PCR also showed that the A values of the MIP 1α mRNA expressed by the cells in n VLDL and ox VLDL group were 15.4 and 14.2 fold as much as that of the control group. Immunocytochemistry showed that the A values of the MIP 1α protein expression in the cells (brown granular substance) in n VLDL and ox VLDL group were significant higher than that of the control group. Analysis of variance showed a significant difference among groups (p<0.05). Conclusion n VLDL and ox VLDL were able to induce MIP 1α mRNA and protein expression in human umbilical vein endothelial cells at a high level, and may play an important role in atherogenesis through enhancing recruitment of monocytes to the intuma.