We recently published evidence of the presence of circulating antibodies in the sera of patients who had the diagnosis of premature menopause syndrome. This led to the question: Is there a circulating antibody in the sera of patients with premature menopause syndrome which interferes with gonadotropin-luteinizing hormone (LH) receptor interaction on the luteal cell surface? Serum samples from 14 women with the diagnosis of Premature menopause syndrome were examined to see whether they would block the binding of 125I-labeled human chorionic gonadotropin (hCG) to human corpora lutea. All patients had spontaneous cessation of menses before the age of 35 years and documentation of increased gonadotropin secretion and failure of estrogen secretion. When the sera of the study group were incubated with 125I-labeled hCG and LH receptor from human corpora lutea, no difference in binding was observed when compared with controls. This suggests that there is no circulating antibody that interferes with hCG-LH receptor interaction and that would thereby lead to loss of ovarian function in premature menopause syndrome.