Introduction: We aimed to investigate serum dynamic thiol and disulfide levels in patients with molar pregnancy (MP), and compare these concentrations with those of healthy pregnant women. Materials and Methods: Forty-one patients who were diagnosed with MP and 41 gestational age-matched healthy pregnant women were included in this prospective study. MP cases were separated in two groups as complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM). Demographic features and thiol/disulfide homeostasis were recorded for each woman. Results: There was a significant correlation between the decrease in the total thiol and native thiol levels in MP patients. However, no significant difference was observed between CHM and PHM groups in terms of serum disulfide levels. Conclusion: OS is increased in MPs both complete and partial moles, as determined by thiol/disulfide analysis.