Aim To investigate whether homocysteine (HCY) could induce human umbilical vein endothelial cells (hUVEC) to express macrophage inflammatory protein 1α (MIP 1α). Methods After exposure of the cultured hUVEC to HCY either at a same concentration for different incubation time or at increasing concentrations but for a same incubation time, the MIP 1α mRNA and protein expression in the cells were determined by reverse transcriptase polymerase chain reaction (RT PCR) and immunocytochemistry, respectively. Results Cultured hUVEC could express MIP 1α mRNA and protein. RT PCR showed that exposure of hUVEC to HCY at a concentration of 0.1 mmol/L for 4, 8 and 16 h, resulted in a 2.08 fold, a 3.26 fold and a 3.35 fold increase in the expression of MIP 1α mRNA in hUVEC, compared with the control group; meanwhile, exposure of hUVEC to HCY at different concentrations (0.1 mmol/L, 0.5 mmol/L and 1 mmol/L) for 8 h, resulted in a 2.08 fold, a 4.35 fold and a 4.57 fold increase in the expression of MIP 1α mRNA in hUVEC as much as the control group, respectively. Immunocytochemistry showed that the absorbance values of MIP 1α protein expression in hUVEC exposed to HCY at a same concentration but for different incubation time mentioned above were 0.071±0.006, 0.081±0.006 and 0.128±0.009 (control group 0.049±0.005), respectively. There was a significantly statistical difference between groups (F=946.70, p<0.01). The absorbance values of MIP 1α protein in hUVEC exposed to HCY at different concentrations but for a same incubation time mentioned above were 0.081±0.006, 0.110±0.009 and 0.118±0.008 (control group 0.049±0.005), respectively, which also showeol significantly statistical difference between groups (F=546.89, p<0.01). Conclusion HCY was able to induce a high expression of MIP 1α mRNA and protein in cultured hUVEC.