Background. A large number of longitudinal studies indicate significantly increased risk of cardiovascular events and death in people with the MetSyn and high plasma levels of triglycerides are an independent risk factor for the development of cardiovascular disease. Apolipoprotein A5 (APOA5) gene, a new member of the APOA1/C3/A4 gene cluster, was identified by comparative sequencing of human and mice DNA by Pennacchio and co-workers in 2001. Since this discovery, variants of ApoA5 gene have been independently assiociated with level of plasma triglyceride in many countries. Human ApoA5 is expressed in the liver then appears in plasma in association with VLDL and HDL and plays a major role in TG catabolism. Variant at ApoA5 gene locus, 1177C>T is located in 3’ UTR which often contains regulatory regions that influence post-transcriptional gene expression. One alteration can be responsible for the altered expression of many genes. Materials and Methods. 152 people with MS for case group and 152 people for control group were selected in this study. MS was diagnosed according to IDF criteria and serum triglyceride levels were determined. DNA from both case and control subjects were extracted from blood samples (200 ml) using “G-spin™ Total DNA Extraction Kit”(iNtRON Biotechnology, Inc). To detect the 1177C>T variation of ApoA5 gene, using High Pure PCR Template Preparation Kits, a forward primer 5’-CTCTGAGCCTCTAGCATGGTTGAGT- 3’ and the mismatch reverse primer 5’-GAGCATTCCCAAATGAGCAC-3’ were used to create the HinfI restriction site. Results. There were 304 total subjects included males 50.3% (153) and female 49.7% (151) in our study. Incident of CC genotype was 71.1% (216), CT genotype was 25% (76) and TT genotype was 3.9%, TAG level was higher in males than females in both groups (p=0.016, ð=0.001) for CC genotype and also, higher with MS in males for CT genotype (p=). But, TAG level was no significant difference among three genotypes in group with MS subjects (male p=0.236, female p=0.881). Conclusion: The TT genotype of the ApoA5 gene 1177C>T polymorphism frequency was 2.9% in control subjects and 4.9% in subjects with MS. However, TG level was not differ in both groups for TT genotype, TAG level in males was higher compared with females (p=0.016 in control, p=0.001 in group with MS).