There is some evidence that chronic obstructive pulmonary disease (COPD) and metabolic syndrome may be related, perhaps through systemic inflammation, which is common to both. However, the association between the two conditions has not yet been clearly shown. The present study involved 7,358 adults aged > or =50 yrs from a population-based survey who underwent spirometry, a structured interview and measurement of fasting metabolic marker levels. Airflow obstruction (forced expiratory volume in 1 s/forced vital capacity ratio of less than the lower limit of normal) was present in 6.7%, and the International Diabetes Federation metabolic syndrome criteria were met by 20.0%. The risk of metabolic syndrome was higher in those with airflow obstruction than in those without (odds ratio (OR) 1.47; 95% confidence interval (CI) 1.12-1.92), after controlling for potential confounders. Of the five components of metabolic syndrome, only central obesity was significantly associated with airflow obstruction (OR 1.43; 95% CI 1.09-1.88) after adjusting for body mass index. A similar association was observed in both never and current smokers. In this Chinese sample, airflow obstruction was associated with metabolic syndrome, and, in particular, its central obesity component. This may help explain the increased risk of cardiovascular diseases in COPD, and so could guide future clinical practice.