A retrospective study was made of 74 women who had received estrogen continuously, cycled with progesterone, for menopausal symptoms over an average 57-month period. Treated patients were compared with control patients from the same private practice. Vabra endometrial aspiration biopsies showed no statistical differences between 25 treated and 28 untreated patients in the frequency of normal, inactive, hyperplastic or neoplastic specimens. The most common finding in the treated group was a secretory response, which suggests that progesterone exerts an antiestrogen effect even when estrogen is given on a continuing basis. There is evidence that the vaginal maturation index in the postmenopausal patient, although helpful in determining the current state of her systemic estrogen activity, may not reflect the effect of estrogen on the endometrium. Estrogen therapy has no absolute predictable correlation with endometrial histology. Thus, the information from routine endometrial curettage is essential to evaluate the status of all treated patients. Among all hormone-treated patients (74), weight decreased over time, blood pressure, blood sugar and cholesterol levels were relatively unchanged, and Papanicolaou smear classes improved.