Background: Occupational pesticide exposure has been associated with oxidative stress and DNA damage, a possible mechanism for cancer and neurological diseases. Only few studies have been performed in environmentally exposed populations. We studied pesticide exposure and oxidative stress in pregnant women who live nearby banana plantations. Methods: We obtained repeat urine samples (n=862) from 445 pregnant women from the ISA birth-cohort study. We measured pesticide metabolites (µg/L) for chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), mancozeb (ethylene thiorurea (ETU)), pyrimethanil (hydroxy pyrimethanil (OHP), 2,4-D (2,4-D) and synthetic pyrethroids such as cypermethrin, deltamethrin and cyfluthrin (3-PBA, DCCA); as well as a biomarker for oxidative stress (8-hydroxy-2'-deoxyguanosine (8-OH-dG)). We associated log-transformed specific-gravity corrected pesticide metabolite concentrations with log-transformed specific gravity corrected 8-OH-dG (ug/L) using linear mixed-effects models. Metabolites and potential confounders were added stepwise and kept in the final model if p<0.10. Gestational anemia and gestational age were included as covariates. Results: Specific gravity corrected median (25-75th percentile) metabolite concentrations were: TCPy=1.6 (1.1-2.5); ETU=3.1 (2.1- 4.8); OHP=0.4 (0.2–1.1); 2,4-D=0.3 (0.2-0.5); 3-PBA=0.7 (0.4-1.3); DCCA=1.2 (0.6-2.0) µg/L; and 8-OH-dG=4.0 (2.9; 5.3) µg/L. Increased concentrations of TCPy (β=0.08 95% CI=0.04-0.13), DCCA (β=0.09 95%CI=0.05-0.12) and OHP (β=0.02 95%CI=0.00-0.04) were associated with greater levels of urinary 8-OHdG. Conclusions: Our findings suggest chlorpyrifos, synthetic pyrethroids and pyrimethanil induce oxidative DNA-damage in pregnant women which may affect both maternal and infant’s health.