Prenatal glucocorticoids have long-term effects on the kidney and blood pressure that may be mediated by the renin-angiotensin system (RAS). We studied the effects of antenatal betamethasone administration on renin in fetal and adult female sheep. Pregnant sheep received 2 doses of betamethasone or vehicle, at 80 and 81 days of gestation (dGA). Fetuses were delivered within 24 hours following treatment, at 135 dGA, or allowed to continue to term. Plasma and kidney samples were collected from fetal and 1-year-old sheep. Plasma and renal renin and renin messenger RNA (mRNA) were measured. Significant decreases in plasma and renal renin and renin mRNA were apparent in female betamethasone fetuses at 80 dGA (P < .05). At 135 dGA, renal renin concentrations were significantly increased in betamethasone fetuses. At 1 year, renin levels were similar in the 2 groups. These findings suggest that prenatal betamethasone has an immediate effect on expression and secretion of renin. The downregulation of renin at 80 dGA may affect nephron development.