Objective. To assess the growth and control of adrenal androgen secretion in children with virilizing congenital adrenal hyperplasia (CAH) treated with dexamethasone. Method. We examined doses used, control of adrenal androgen secretion, and growth and skeletal maturation of 8 children with CAH treated with dexamethasone beginning in infancy. Results. 3 boys and 5 girls with classical CAH (17-hydroxyprogesterone at diagnosis >20,000 ng/dL) were treated with dexamethasone beginning at diagnosis (<10 days of age). Patients were also treated with fludrocortisone and sodium chloride. The average initial medication dose was 0.1 mg (0.28 +/- 0.015 mg/m(2)); all doses were given in the morning using a dosing syringe to administer a 0.1 mg/mL elixir. The children were treated for 6.5 +/- 2.0 years over which time the change in bone age to chronological age ratio (DeltaBA/DeltaCA) was 0.9 +/- 0.06. Most recent height Z' scores were +0.5 +/- 0.2, and body mass index (BMI) scores were 18 +/- 0.2. Late afternoon levels of 17-hydroxyprogesterone, androstenedione, and testosterone were 780 +/- 238 ng/dL (23.4 +/- 7 nmol/L), 42 +/- 10 ng/dL (1.4 +/- 0.3 nmol/L), and 11.5 +/- 3 ng/dL; (0.4 +/- 0.1 nmol/L), respectively. Conclusions. These observations show that low doses of dexamethasone can be used to effectively treat CAH beginning in infancy.