Nearly half of the world's population is exposed to household air pollution (HAP) due to long hours spent in close proximity to unvented cooking fires. The effect of woodsmoke exposure on oxidative stress was examined by investigating the association between woodsmoke exposure and biomarkers of DNA oxidation (8-hydroxy-2′-deoxyguanosine [8-OHdG]) and lipid peroxidation (8-isoprostane) among control and intervention stove users. HAP exposure assessment was conducted within the framework of a community-randomized controlled trial of 51 communities in San Marcos Province, Cajamarca Region, Peru. The first morning urine voids after 48 h HAP exposure assessment from a subset of 45 control and 39 intervention stove users were analyzed for 8-OHdG and 8-isoprostane. General linear models and correlation analyses were performed. Urinary oxidative stress biomarkers ranged from 11.2 to 2270.0 μg/g creatinine (median: 132.6 μg/g creatinine) for 8-OHdG and from 0.1 to 4.5 μg/g creatinine (median: 0.8 μg/g creatinine) for 8-isoprostane among all study subjects (n = 84). After controlling for the effects of traffic in the community and eating food exposed to fire among all subjects, cooking time was weakly, but positively associated with urinary 8-OHdG (r = 0.29, p = 0.01, n = 80). Subjects' real-time personal CO exposures were negatively associated with 8-OHdG, particularly the maximum 30-second CO exposure during the sampling period (r = − 0.32, p = 0.001, n = 73). 48 h time integrated personal PM2.5 was negatively, but marginally associated with urinary 8-isoprostane (r = − 0.21, p = 0.09, n = 69) after controlling for the effect of distance of homes to the road. Urinary 8-isoprostane levels reported in the available literature are comparable to results found in the current study. However there were relatively high levels of urinary 8-OHdG compared to data in the available literature for 8-OHdG excretion. Results suggest a sustained systemic oxidative stress among these Peruvian women chronically exposed to wood smoke.