Studies have shown increased oxidative stress in patients with chronic airflow limitation; however, the population-based evidence for the association of oxidative stress with pulmonary function is limited. The authors analyzed the association of plasma thiobarbituric acid-reactive substances (TBARS), glutathione, glutathione peroxidase, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox)-equivalent antioxidant capacity with forced expiratory volume in 1 second and forced vital capacity using data collected from 1996 to 2000 in a general population sample from western New York State (n = 2,346). After adjustment for covariates including smoking status, lifetime pack-years of smoking, education, weight, and eosinophils, multivariate analysis showed an inverse association of TBARS with forced expiratory volume in 1 second and forced vital capacity as the percentage of the predicted value (FEV1% and FVC%, respectively), positive associations of glutathione peroxidase with FEV1% and FVC%, and an inverse association of glutathione with FEV1% in men (p < 0.05). The associations of TBARS and glutathione peroxidase with FVC% in men remained statistically significant after adjustment for serum carotenoid levels. There were no statistically significant associations of oxidative stress with pulmonary function in women. These results suggest that oxidative stress may be associated with airflow limitation in men, and that gender differences may exist in the relation of oxidative stress to pulmonary function.