The plasma levels of estradiol were studied in 20 postmenopausal women over a period of 8 h following the ingestion of a single dose of 2 mg estradiol valerate and 2 mg micronized estradiol. The determined plasma estradiol concentrations were correlated with somatometric characteristics and age. Twenty-six postcephalic body measurements, the body weight and six skin-fold thickness measurements were taken and the body mass index computed; estradiol serum concentration was measured before and after administration of micronized estradiol and estradiol valerate, respectively. It was shown that estradiol concentrations obtained after estradiol valerate and micronized estradiol ingestion were dependent on the patient's age as well as on the constitutional type. Additionally, we found that there were differences in the reachable estradiol plasma concentrations following the application of the two preparations. Our results justify the individual and differentiated estrogen replacement therapy of the postmenopausal woman.