In order to evaluate the consistency of the serum estradiol pattern and response and to determine the influence of number of ovary on them in repeat cycles in the same patient, 57 cycles in 24 patients who underwent in Vitro Fertilization-Embryo Transfer or Gamete Intrafallopian Transfer in Seoul National University Hospital. The patients were stimulated by follicular stimulating hormone and human menopausal gonadotropin and classified as high(${geqq}$400 pg/ml) and low(<400 pg/ml) response group according to preovulatory estradiol concentration and classified as three estradiol patterns (A,G.B) according to Jones criteria. Seventeen(89.5%) of 19 patients in when a high response to ovulation induction in their first cycle showed a high response. 40%(2/5) of the second ovulation induction cycle were low response in the patient whose first cycle resulted resulted in a low response. Serum estradiol pattern in the first ovulation induction cycle tended to be repeated in the second cycle. Women with high response tended to be more likely to have A and G patterns and less likely to have a cancellation than those with low response. One-ovary patients were at higher risk for inadequate ovulation induction response.