Objective: To investigate whether administration of genistein can improve hormonal changes (estradiol and follicle stimulating hormone (FSH)] , heat shock protein 70 (Hsp70) expression, and thickness of vaginal epithelial cells in a rat model of vaginal atrophy. Methods: Twenty-five multiparous female rats were divided into five groups, namely the control group (without ovariectomy), the ovariectomy only group, and the ovariectomy groups 1, 2 and 3 receiving genistein at the doses of 0.045, 0.090 and 0.180 mg/kg body weight/day, respectively. Estradiol, FSH, and Hsp70 expression were analyzed by using the immunoassay technique. Analysis of the thickness of the vaginal epithelium was performed by histology. Results: Ovariectomy significantly decreased estradiol levels compared to the control group (P<0.05). All doses of genistein significantly increased levels of estradiol in rats with vaginal atrophy compared to the ovariectomy only group (P<0.05). Ovariectomy significantly increased FSH levels compared to the control group (P<0.05). All three doses of genistein restored FSH levels comparable to those in the control group (P>0.05). Ovariectomy significantly increased parabasal cell Hsp70 expression compared to the control group (P<0.05). Of all the genistein doses, only the dose at 0.045 mg/kg body weight/day restored the expression of Hsp70 to levels in the control group (P>0.05). Conclusions: Genistein is able to increase the thickness of the vaginal epithelium through hormone modulation and cellular stress suppression. Genistein is beneficial in the form of a herbal or altative food for improvement of vaginal atrophy due to menopause.