Excess endothelial production of reactive oxygen species (ROS) has been found to play a major role in the pathogenesis of many cardiovascular diseases. Ageing is a primary risk factor of cardiovascular diseases, however the role of oxidative stress in the development of vascular dysfunction in the elderly remains unknown. In this study we used wild-type C57BL/6 J mice, at young (3–4 m) and old (20–24 m) age to investigate the potential role of ROS in age-related metabolic disorders and vascular dysfunction. The body weight, heart weight and fasting serum glucose were recorded. There was no significant difference in the heart/body weight ratio, and the fasting glucose between the two groups. However, there was a significant increase in blood pressure in ageing mice (141 mm Hg) compared to young mice (126 mm Hg) measured by volume pressure recording tail plethysmography. Vascular tone was examined using aortic rings in an organ bath. There was no significant difference in vessel relaxation to a NO donor (sodium nitroprusside) between the young and ageing mice. However, there was a significant decrease in endothelium- dependent vessel relaxation to acetylcholine in ageing mice compared to young mice. There was a significant increase in the levels of superoxide production by the ageing vessels compared to the young controls as measured using lucigenin-chemiluminescence. In conclusion, there was a significant increase in the levels of ROS production in the vasculature of ageing mice, which might contribute to the age-related endothelial dysfunction and high blood pressure.