In conclusion, the results of the present meta-analysis suggest that heterozygous and homozygous variant carriers of the MTHFR Glu429Ala polymorphism are significantly associated with increased bladder cancer risk in individuals of Middle Eastern descent, with no evidence of an association between this polymorphism and bladder cancer risk in individuals of Chinese, European and American descent. Here, MTHFR is linked to urinary bladder carcinoma.