Plasma total glutathione (GSH) content (reduced plus oxidized) was estimated in varying grades of cervical intraepithelial neoplasia (CIN) and in invasive cervical cancer. The values were compared with age-matched control women. The results show significantly lower level of plasma GSH in CIN III and invasive cancer compared to controls (0.724 versus 1.082 and 0.622 versus 1.082 mumol/ml of plasma, P < 0.05). Further, the odds ratio analysis showed high plasma GSH content was found to be protective against the development of cervical cancer. The results suggest a plausible association of plasma GSH with cervical carcinogenesis. The quantitative changes occurring in plasma total glutathione during cervical carcinogenesis is a useful finding and might represent a systemic biochemical marker for precancerous and cancerous lesions of the uterine cervix.