Circulating levels of osteoprotegerin (OPG) have been shown to be increased in patients with cardiovascular disorders and diabetes. The aim of this study was to determine serum OPG levels in women with previous gestational diabetes (GDM), and to investigate the relationship between OPG and carotid intima media thickness (IMT) and circulating cardiovascular risk factors. Serum OPG was measured in 46 women with previous GDM and 30 age-matched healthy controls. Carotid IMT was evaluated. Serum lipid, insulin and hsCRP levels, plasma fibrinogen, vWF and PAI-1 levels were measured. Serum OPG levels tended to be increased in women with previous GDM (p=0.058). Carotid IMT was increased in the study group. Women with previous GDM had elevated levels of hsCRP and PAI-1. OPG levels were positively correlated with age, fasting and post-load glucose levels, hsCRP, and carotid IMT. Multiple regression analysis showed that serum OPG was a statistically significant predictor for elevated carotid IMT. Our results revealed that OPG levels tended to be elevated in women with previous GDM. Significant association of OPG with carotid IMT suggested that OPG might play a role in the pathogenesis of endothelial dysfunction in women with previous GDM.