Native glycogen content and glycogen metabolizing enzymes including amylophosphorylase, amylo-1, 4-1, 6-transglucosidase, and glycogen synthetase were studied in the squamous epithelium of surgically removed uterine cervices from women with menstrual cycles and postmenopausal women. No cyclic alteration in the distribution patterns of native glycogen or glycogen metabolizing enzymes was apparent in women with menstrual cycles before or after ovulation, possibly due to persistently high levels of estrogen. Despite the thinness of the squamous epithelial layer in the cervices, as well as the atrophic endometrium, of some postmenopausal women, signifying a low estrogen production, native glycogen and glycogen metabolizing enzymes were present in the cervical squamous epithelium with the same distribution pattern as in women with menstrual cycles. This suggests a glycogen-metabolizing mechanism in the cervical squamous epithelium which is highly sensitive to estrogen or some other glycogen-metabolizing hormone. The stromal theca cell is suggested as a possible source of hormones responsible for glycogen maintenance in the cervical squamous epithelium of the postmenopausal woman, although the adrenal cannot be ruled out at present as an alternate source. The reciprocal relationship between native glycogen and keratin as brought out in a comparison of normal cervical squamous epithelium with the squamous epithelium of the cervix in leukoplakia has been demonstrated. The absence of glycogen synthetase as well as native glycogen in the leukoplakic cervical squamous epithelium reproduces a pattern normally seen in the epidermis.