Ovulation was induced with one-quarter tablet (12.5 mg) of clomiphene citrate given for five days to three oligoovulatory patients who had consistently formed functional ovarian cysts when given 50 and 25 mg of clomiphene citrate for five days. Two of the patients had polycystic ovary syndrome and the other had hypothalamic dysfunction associated with an eating disorder. On clomiphene citrate 12.5 mg for five days, one patient conceived, another produced inadequate cervical mucus but later conceived after in vitro fertilization and embryo transfer, and the third woman, who had concomitant fallopian tube disease, ovulated but has not conceived. Women oversensitive to clomiphene citrate can be effectively treated with very low doses of the drug. Perhaps other oligoovulatory patients may benefit from lower than currently recommended clomiphene citrate doses.