This study investigated serum lipid peroxidation, antioxidant capacity, and trace element levels in Korean women as related to uterine cervical neoplasia. Twenty-eight subjects had cervical intraepithelial neoplasia (CIN), 36 had invasive cervical cancer, as determined by a colposcopically directed biopsy, and controls included 44 subjects with normal colposcopic findings. Significantly lower selenium (Se) and zinc (Zn) levels and higher copper/Zn ratios were found in both CIN and cancer patients compared with the controls. Serum malondialdehyde levels decreased significantly in the order CIN>cancer>control, implying the involvement of reactive oxygen species at the precancerous stage, that is, prior to progression into invasive cervical cancer. Serum glutathione peroxidase activity was significantly lower in patients with CIN or cancer than controls, and total antioxidant ability decreased from controls to CIN to cancer (P < 0.0001). This study demonstrated the involvement of lipid peroxidation, decreased Se and Zn levels, and an impaired serum antioxidant system in the pathogenesis of cervical dysplasia. Further research is needed to examine the possibility of an effective chemopreventive treatment in cervical cancer based on enhancing the endogenous antioxidant system.