Clinical characteristic of the hyperprolactinemia were studied in 101 cases and effects of Bromocriptine were investigated in 57 cases with hyperprolactinemic anovulation. 1. Lactation was observed in 93.1% of the cases with hyperprolactinemia. There was no relationship between the degree of lactation and Prolactin (PRL) levels. 2. Hyperprolactinemia had no influence on basal gonadotropin levels. 3. In hyperprolactinemic anovulatory syndrome, a negative correlation between estradiol and PRL levels was found. PRL levels in the second grade amenorrhea were higher than those in other grade. 4. In LH-RH test, there was no relationship between PRL and LH-RH test. 5. With Bromocriptine therapy, ovulation was induced in 45 cases and pregnancy was successful in 31 cases. 15 cases of pregnancies were delivered of normal babies and 3 cases fell into abortion. 6. The initial dose of Bromocriptine was 2.5 mg/day. The dosage was increased by determining the PRL as index. 7. Cases with severe anovulation and high PRL levels, required prolonged administration. 8. 15 cases who had no ovulation by Bromocriptine administration for one month, ovulated successfully by clomiphene combined with Bromocriptine. 9. In 31 pregnant cases, there was no significant symptoms of pituitary tumor during pregnancy.