Erectile dysfunction is a multifactorial disease; it has been demonstrated that endothelial dysfunction plays an essential role in the pathogenesis of this disease, and Vitamin D deficiency is considered to favor endothelial lesions. Our study, based on a group of 58 patients who have erectile dysfunction and a control group of 26 healthy subjects, tends to confirm that low levels of vitamin D could potentiate the severity of erectile dysfunction, promoting endothelial dysfunction. Statistical analysis using the Pearson's correlation criteria showed a robust and significant correlation between vitamin D levels and erectile dysfunction severity (ρ=0.752, p<0.000) according to the SHIM (Sexual Health Inventory For Men) questionnaire. Also, in patients with erectile dysfunction, there is a strong association between vitamin D and testosterone levels (ρ=0.728, p<0.000). At the same time, a negative correlation between vitamin D and BMI (ρ=-0.517, p<0.000); cholesterol (ρ=-0.560, p<0.001), and triglycerides(ρ=-0.529, p<0.005) was observed. Also, a moderate correlation between erectile dysfunction severity degree and testosterone levels (ρ=0.544) was also detected, and the same severity parameter of erectile dysfunction correlates negatively with cholesterol levels (ρ=-0.534). In its turn, the testosterone level correlates negatively with other biochemical indices: cholesterol (ρ=-0.694) and triglycerides (ρ=-0.670). Vitamin D level reduction, concomitantly with decreased testosterone and increased cholesterol, contributes to the development and maintenance of erectile dysfunction, more probably through endothelial mechanisms. The assessment of vitamin D values can be used as an independent marker in erectile dysfunction assessment. Thus, one of the diagnostic tests recommended for erectile dysfunction should be the determination of the vitamin D serum level.