Changes in follicular stimulating hormone (FSH), luteinizing hormone (LH) and follicular sizes were observed in 10 patients with chronic anovulation during electroacupuncture treatment. Seven cases were diagnosed as suffering from polycystic ovary syndrome, 2 from dysfunctional uterine bleeding, and 1 from hypogonadotropic amenorrhea. Among them 8 cases complained of infertility for an average of 2. 7years. Ovulation was confirmed by pregnancy or the combination of biphasic basal body temperature and ultrasonographic signs. During one course of 3 consecutive days of electroacupuncture treatment on acupoints Guanyuan (Ren 4), Zhongji (Ren 3), Zigong (Extra 16) and Sanyingjiao (Sp 6), ovulation resulted in 5 patients (ovulating group) and 3 of the 4 infertile women became pregnant. Five cases failed to ovulate (non-ovulating group), 3 of them reached a biphasic basal body temperature without ovulatory signs on ultrasonograph. Serum FSH, LH values and FSH pulse frequency increased significantly during-electroacupuncture treatment in the ovulating group (from 2. 10±0.42 pulses/4h to 3. 70±1.64 pulses/4 h), but not in the non-ovulating group. No apparent change was found in LH pulse frequency, or in pulse amplitudes for FSH and LH. In the ovulating group, diameters of ovarian follicules markedly increased, but their growth was limited in the non-ovulation group. The results suggest ovulation may be induced by electroacupuncture via a regulation on the hypothalamic-pituitary function, leading to normal secretion of FSH and LH.