The interaction between immune cells and endothelial lining of blood vessels is vital in many processes such as inflammatory and immune responses as well as cancer cell metastasis. The expression level of VCAM-1 is regulated by many factors including the promoter activity that is possibly affected by the single nucleotide polymorphisms (SNPs) present in the promoter. There are previous reports suggesting an important role for rs3783605 at -420 position in the pathogenesis of VCAM1-associated diseases. This is possibly due to the effect of this SNP on promoter activity and gene expression. Therefore, present study was designed to investigate the effect of rs3783605 on the activity of VCAM-1 gene promoter in human umbilical vein endothelial cells (HUVEC). In this study, two appropriate expression vectors containing VCAM1 promoter with different alleles of rs3783605 were constructed to express the Green Fluorescent Protein (GFP). Expression vectors were transfected into HUVECs and their EGFP expression level was assessed by the fluorescent microscopy and real-time PCR. Bright green fluorescence was seen in the HUVECs transfected by expression vector containing CMV promoter. The expression level in the cells transfected by vector containing promoter with A allele of rs3783605 was 0.14888 folds and G allele was about 0.37851 folds of cells transfected by vector having CMV promoter (p<0.001). Moreover, HUVECs transfected by G allele of rs3783605 showed about 2-fold higher transcriptional activity compared with the A allele, (p=0.049). Our findings showed that rs3783605 polymorphism may play a role in VCAM-1 gene expression. Therefore, it is likely that it may have an important role in the pathogenesis of VCAM1-associated diseases and tumor metastases.