Objectives: This study was designed to investigate the effects of Hyeolbuchukeotang( HCT) on the Estradiol Valerate(EV) induced Polycystic Ovaries and the Implantation of rats. Methods: PCO was induced by single intramuscular(IM) injection with EV in female rats. Normal group(n=8) were injected with sesame oil and orally administrated distilled water for 60 days. Control group(n=8) were injected with EV and orally administrated distilled water for 60 days. HCT treated group(n=8) were injected with EV and orally administrated HCT for 60 days. At the end day of experiment, we measured weights of body, ovaries, adrenal glands, uterus and contents of serum LH, FSH, ADD. The histomorphometrical changes of ovaries were also evaluated. And we observed the NGF and CRF expression by immunohistochemistry. Also we observed the mating and count the number of implantation. Results: - The weights(mg) of ovaries in HCT treated group($58.9{pm}6.5$) were significantly increased (p<0.01) compared with control group ($42.3{pm}8.5$). - The number of mature follicles in HCT treated group($9.8{pm}2.6$) was significantly increased (p<0.01) compared with control group($6.1{pm}2.1$). - The number of cystic follicles in HCT treated group($1.6{pm}1.2$) was significantly decreased (p<0.01) compared with control group($3.8{pm}1.5$). - The value of serum FSH(mIU/ml) in HCT treated group($3.870{pm}2.151$) was significantly decreased(p<0.05) compared with control group($10.476{pm}6.294$). - The expression of NGF-immunoreactive cells in the ovarian cells in HCT treated group was lesser observed than control group. - The number of implantation in HCT treated group($7.4{pm}1.8$) was significantly increased (p<0.05) compared with control group($3.1{pm}4.4$). Conclusions: Hyeolbuchukeo-tang(HCT) is effect on polycystic ovaries and the implantation of rats by EV-induced.