Previous studies reported impaired cerebral cortical gray matter (CGM) development and neurodevelopmental impairment after neonatal dexamethasone treatment for chronic lung disease (CLD) in preterm newborns. No long-term effects on neurocognitive outcome have yet been shown for hydrocortisone treatment. A prospective study was performed to evaluate the brain growth at term in preterm infants who did receive neonatal hydrocortisone for CLD. Thirty-eight preterm infants (n = 19 hydrocortisone, n = 19 controls) were matched for gestational age at birth. Gestational age and birth weight were 27.0+/- 1.4 versus 27.6+/- 1.1 wk (p = ns) and 826+/- 173 versus 1017+/- 202 g, respectively (p < 0.05). Infants were studied at term equivalent age. Hydrocortisone was started with a dose of 5 mg/kg/d for 1 wk, followed by a tapering course over 3 wk. A 3D-MRI technique was used to quantify cerebral tissue volumes: CGM, basal ganglia/thalami, unmyelinated white matter, myelinated white matter, cerebellum, and cerebrospinal fluid. Infants who were treated with hydrocortisone had more severe respiratory distress. There were no differences in cerebral tissue volumes between the two groups at term equivalent age. In conclusion, no effect on brain growth, measured at term equivalent age, was shown after treatment with hydrocortisone for CLD.