Purpose. To determine the urinary levels of 1-hydroxypyrene (1-OHP), 2-naphthol (2-NAP) and cotinine in pregnant women exposed to environmental tobacco smoke (ETS). Methods. One-hundred twenty-four pregnant women from four hospitals were interviewed using a questionnaire. Data obtained included demographic information and life styles. The levels of 1-OHP and 2-NAP in urine specimens from all participants were analyzed by HPLC-Fluorescence; urinary cotinine levels were measured by HPLC-photodiol instrumentation. Results. Urinary levels of 1-OHP, 2-NAP and cotinine in the ETS exposure group were higher than the non-exposure group; only urinary cotinine levels differed significantly between the two groups. Urinary levels of 1-OHP were positively correlated with 2-NAP (r=0.14) and cotinine (r=0.09), and 2-NAP and cotinine (r=0.12); however, no significant correlation was found. Conclusions. Urinary cotinine and 2-NAP levels can be used as biomarkers to measure the exposure to poly aromatic hydrocarbons (PAH) emitted from burning cigarettes.