Eight women who had been maintained on a combined estrogen-androgen drug since hysterectomy and bilateral oophorectomy 2 yr previously were investigated for changes in sexual behavior during the course of 1 treatment cycle. Following intramuscular injection of both sex steroids, plasma estradiol levels were within the normal range of young, cycling women but plasma testosterone exceeded the upper limit of normal female values. Sexual motivational behaviors (desire, fantasies and arousal) covaried with plasma steroid levels. Rates of coitus and orgasm, however, were unrelated to the changing levels of circulating hormones. A differential effect of the sex steroids on various aspects of sexual functioning was thus confirmed.