Few and contrasting data have reported vascular endothelial dysfunction and increased serum levels of endothelial dysfunction and inflammatory markers in women with previous gestational diabetes mellitus (pGDM). We aimed at evaluating 6.5 years after delivery: intimal medial thickness (IMT), and C-reactive protein (CRP), interleukin-6 (IL-6), E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) levels in 82 non-pregnant pGDM and 113 control women without pGDM. A subgroup of 21 women, taken from the pGDM group, showing current normal BMI, and no metabolic abnormalities, was separately analysed. All the subjects were free of medication and non-smokers. Women with pGDM, independently by their current BMI and presence of metabolic abnormalities, showed significantly higher E-selectin, ICAM-1 and IMT values than controls. IMT proved to be significantly associated with pGDM in a regression model, after adjustments for BMI, waist circumference, blood pressure, and glucose values (beta=0.046; 95% CI 0.028-0.064). In all pGDM women, E-selectin, ICAM-1, IL-6 and hs-CRP values were significantly associated with IMT in the same model. Post-GDM women, despite being currently free from metabolic abnormalities, showed higher values of markers of endothelial dysfunction and IMT than controls, consistent with an increased future cardiovascular risk.