Background: To study the association of the most common methylenetetrahydrofolate reductase (MTHFR) genetic polymorphisms C677T and A1298C with retinal vein occlusion (RVO) in a Spanish population. Methods: Case-control study involving 359 subjects, 183 unrelated native Spanish patients diagnosed with RVO, distributed in central or branch RVO, and 176 healthy controls. Two SNPs located in the gene MTHFR, C677T (rs1801133) and A1298C (rs1801131) were analyzed by DNA sequencing and TaqMan assays. Results: A high prevalence of the MTHFR variants T and C of the SNP C677T and A1298C, respectively, was observed in our population. Specifically, 88.07% of controls and 85.25% of RVO patients have at least one of these variants. However, the prevalence of these variants was not significantly different when comparing RVO patients and controls. The variant T of C677T was identified in 60.65% of RVO patients and 59.10% of control subjects, while the variant C of A1298C was present in 46.45% of RVO patients and 51.14% of controls. No association of dyslipidemia, diabetes mellitus, glaucoma, thyroid disease and renal disease with RVO was observed, while hypertension was significantly higher in the RVO patients (p < .0001). Conclusions: The MTHFR variants, T of C677T and C of A1298C, did not significantly increase the risk of suffering RVO in a Spanish population and therefore additional risk factors are contributing to the onset of the disease.