Epidemiological studies have suggested that phthalate exposures were associated with adverse reproductive outcomes, such as low oocyte yield and reduced embryo quality, but the underlying mechanisms remained largely unknown. Oxidative stress may be a potential contributor to phthalate-induced adverse reproductive outcomes. To explore the associations between phthalate exposure and levels of oxidative stress among women seeking in vitro fertilization (IVF), we measured the concentrations of eight phthalate metabolites and bio-markers of oxidative stress, including 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and total antioxidant capacity (TAC), in follicular fluid (IT) samples collected from 332 women. Multivariable linear regression models were used to assess the associations between phthalate metabolites and biomarkers of oxida-tive stress in FF samples. The concentrations of most tested phthalate metabolites were positively associated with the 8-OHdG levels. The metabolites of di-(2-ethylhexyl) phthalate (DEHP) were inversely associated with the TAC levels. The concentrations of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) were positively associated with the MDA levels. Our results revealed a positive as-sociation between phthalate metabolites and oxidative stress levels in IT, while more toxicological and epidemiological studies are required to confirm our findings. (C) 2020 Elsevier B.V. All rights reserved.