Background and aims. Diabetic nephropathy, one of the most common long term complications of diabetes, represents the major leading cause to the end stage renal disease (ESRD). ESRD has a complex genetic component. In some studies, MTHFR polymorphisms have been found to increse the susceptibility for diabetic nephropathy or ESRD in both type 1 (T1DM) and 2 diabetes (T2DM). We found no information regarding association between MTHFR C677T polymorphism and Romanian ESRD patients. The aim of this study was to evaluate the impact of MTHFR C677T alleles on the ESRD development in T1DM and T2DM patients. Material and methods. Clinical informations and blood samples were collected from 310 unrelated Caucasians, fall into four groups: dD1 - dialyzed T1DM (n=60); dD2 -dialyzed T2DM (n=50); dnD - dialyzed non-diabetic patients (n=100), HC - healthy controls (n=100). PCR-RFLP analysis was performed for genotyping the MTHFR C677T polymorphism. Results. The frequencies of MTHFR C677T genotypes were in Hardy-Weinberg equilibrium. The genotype MTHFR 677TT was more frequent in dD1, dD2 and dnD compared with HC group and was found to increases the statistical risk for ESRD. The higher risk was found in dD1 (OR=2,8) group. This risk decreases in dD2 (OR=2,5; 95% CI: 0,7<OR.