In order to define the clinical characteristics of Korean women with polycystic ovary syndrome, clinical symptoms, biochemical features and ultrasonographic findings were determined in ninety PCO patients. Frequency of clinical manifestations were as follows:acne 42%, overweight 31 %, oily skin 14 %, hirsutism 10%. Relatively low frequencies of hirsutism is recognized in patients with Korean PCO syndrome. Mean(${pm}$S.E.) of each hormone was:testosterone 1.18${pm}$1.07ng/ml, LH 21.47${pm}$${pm}$2.6mIU/ml, FSH 7.26${pm}$2.67mIU/ml, LH/FSH ratio 2.94${pm}$1.29, prolactin 25.48${pm}$46.33ng/ml, DHEA-S 333.78${pm}$309.60ng/dl, 17-0HP 1.72${pm}$1.74ng/ml. Mean 17-OHP after ACTH stimulation test was 5.07${pm}$12.01ng/ml. Ultrasonographically measured mean ovarian volume were $11.02{pm}5.92cm^3$ in right and $9.23{pm}5.64cm^3$ in left and small sized multiple subcapsular follicular cysts were noted in 43 patients (47.9%) with PCO syndrome.