Little information is available on the role of environmental chemical exposure in oxidative stress. This study was designed to investigate whether exposure to environmental chemicals, such as polycyclic aromatic hydrocarbons, volatile organic compounds, bisphenol A or phthalates, induces oxidative stress in urban adult populations. A total of 960 adults dwelling in urban areas were evaluated between April and December 2005. To assess environmental chemical exposure, we measured urinary levels of 1-hydroxypyrene, 2-naphthol, hippuric acid, methyl hippuric acid, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, and mono-butyl phthalate and bisphenol A. Urinary malondialdehyde and 8-hydroxydeoxyguanosine were also measured to evaluate oxidative stress. Significant dose-responsive relationship was found between urinary concentrations of the chemical exposure biomarkers and oxidative stress levels in simple regression analyses (P<0.05). Regression coefficients of these exposure biomarkers except bisphenol A remained significantly in the multiple regression models after controlling for age, sex, weight, smoking, and exercise for at least one of the two oxidative stress biomarkers (P<0.05). The oxidative stress biomarkers significantly affected the indicators of insulin resistance, particularly glucose level. This study indicates that environmental chemical exposure is associated with oxidative stress in urban adult populations and suggests that exposure to certain environmental chemicals might contribute to insulin resistance.