Patients suffering from normogonadotrophic anovulation and infertility are initially treated with clomiphene citrate. Those who do not respond to clomiphene citrate usually receive gonadotrophin treatment which is labour-intensive, expensive, and associated with an increased risk of multiple pregnancies and ovarian hyperstimulation syndrome. We treated 22 patients with clomiphene resistant normogonadotrophic anovulation with naltrexone (an opioid receptor blocker) alone or naltrexone in combination with an antioestrogen. In 19 patients ovulation and resumption of a regular menstrual cycle was achieved and in 12 out of 19 a singleton pregnancy was observed. In conclusion, ovulation can be induced successfully using naltrexone alone or naltrexone in combination with an anti-oestrogen in clomiphene citrate resistant anovulatory patients. Compared to gonadotrophin induction of ovulation, this method is safe, simple and inexpensive.