To evaluate whether obesity and smoking habit may accelerate the age-related increase of oxidative stress.The Oxidative-INDEX, a score reflecting both oxidative and antioxidant counterparts, was estimated in 179 subjects (50 males, aged 16–79 years).Oxidative stress results were elevated in obese and smoker subjects. Adjusted logistic regression analysis indicated obesity and smoking as independent variables for elevated Oxidative-INDEX (odds ratio=4.8 and 3.1, respectively). Oxidative-INDEX steadily rises at a mean rate of 5.3% (0.017 AU) per year in the overall population, showing twice and three times higher annual rate increase in smokers and obese subjects.Our results suggest the pro-ageing effects of cigarette smoking and obesity by a more rapid and sharp elevation of the oxidative stress status.