Following the NIH Consensus Conference on Antenatal Corticosteroids (ANCS), we conducted a survey (questionnaire) of self-reported practice of all USA members of the Society of Perinatal Obstetricians (SPO), n=1420, to determine the prevalence and nature of ANCS use in clinical practice in the USA. After 3 mailings there was a 68% response rate (n=963), of which at least 64% were board certified in Maternal-Fetal Medicine. All practicing members of the SPO use ANCS. Of those responding, 89% use betamethasone, mean dose 12±7 mg, given q12 (33.1%) or q24 (66.5%), to fetuses of gestational age 24.1 to 33.9 weeks. The rest use dexamethasone. Twenty eight% (n=267) would treat if delivery is expected to occur within 6h, 55% (n=526) if within 6-12h, and 97%(n=932) if within 24-48h. ANCS are used in the presence of prolonged premature rupture of membranes (84%), pregnancy induced hypertension (94%), gestational diabetes treated with insulin (85%), and in multiple gestation without changing the dose. Of those using betamethasone, 96% give more than one course of ANCS, usually weekly (92%), with 92% retreating whether active labor persists or recurs, and at least 49% retreating even after preterm labor has stopped and the patient has been discharged home. 58% would give a maximum of 6 or more courses, 21% 4-5 courses, 12% 3 courses, and 6% only 2 courses. We conclude that as of March 1995, the majority of USA members of the SPO are compliant with most recommendations of the NIH Consensus Conference. However since there are no data on the benefit or safety of multiple courses of ANCS, this practice clearly needs further study.