Objective: To investigate the association between single nucleotide polymorphisms (SNPs) at C677T of methylenetetrahydrofolate reductase (MTHFR) gene and susceptibility to splanchnic vein thrombosis (SVT). Methods: The relevant case-control studies regarding MTHFR C677T SNPs and SVT were collected by searching several national and international online databases. The associations of the genotypes and allelic genes of MTHFR with SVT were analyzed by Stata 12.0 software. Results: Nineteen studies were finally included involving 1 194 SVT patients and 1 988 control subjects. SVT were divided into 3 subgroups: portal vein thrombosis (PVT), Budd-Chiari syndrome (BCS) and mesenteric vein thrombosis (MVT). MTHFR C677T SNPs were significantly associated with SVT under dominant model CC vs. (CT+TT) (OR=0.51, 95% CI=0.34–0.76, P=0.001) and additive model CC vs. TT (OR=0.33, 95% CI=0.23–0.47, P<0.001); MTHFR C677T SNPs were significantly associated with SVT (OR=2.27, 95% CI=1.77–2.90, P<0.001) and PVT subgroup (OR=2.23, 95% CI=1.57–3.17, P<0.001) under recessive model TT vs. (CT+CC); MTHFR C677T SNPs were significantly associated with SVT (OR=1.84, 95% CI=1.33–2.55, P<0.001) and MVT subgroup (OR=1.64, 95% CI=1.14–2.36, P=0.008) under allele gene model. Conclusion: There is an association between MTHFR C677T SNPs and SVT susceptibility, and those with TT genotype and T alleles may have increased risk of SVT.