Objective:To study the effects of raloxifene on expression of estrogen receptors(ERs) in bone and endometrium of ovariectomized rats and to presume its tissue-specific mechanisms.Methods:Forty four-month-old Sprague-Dawley female rats were randomized into four groups(n=10):sham-operated(SHAM) group,ovariectomized(OVX) group,ovariectomized plus estradiol valerate treated (OVX+E2) group,ovariectomized plus raloxifene treated(OVX+RAL) group.They were sacrificed after lavaged for 12 weeks.Vertebrae L6 and right femur shaft and the uterus were excised.The uteri were attained for endometrium pathomorphology and histomorphometry.ER-αand ER-βmRNA expression of endometrium samples and femur shaft and vertebrae L6 were tested by real-time RT-PCR.