The aim of this study was to evaluate the predictive value of corrected head circumference (HC) centiles at 2 years of age with respect to developmental performance in a series of high-risk neonatal intensive care unit (NICU) survivors with microcephaly. The study used a retrospective review of the clinical files of children seen in a clinic devoted to the follow-up of all high-risk survivors of a hospital's level III NICU. All children with microcephaly (occipital-frontal circumference below the 2nd centile for sex) at 2 years of age were identified. The HC obtained at 2 years was corrected to the ages for which the absolute HC corresponded to either the 50th or 2nd centile for the child's sex. Of 312 high-risk patients followed, 38 (12.2%) were microcephalic. Fifteen performed below the 50th age-corrected HC centile (severe developmental delay), 12 performed between the 50th and 2nd age-corrected HC centile (moderate developmental delay), and 11 performed above the 2nd age-corrected HC centile (mild developmental delay). The absolute value of HC measurement was not a predictor of developmental performance. Of all clinical factors evaluated, only coexisting epilepsy was found to be a significant predictor of less than the 50th age-corrected HC centile developmental performance (chi2=6.134, p=0.01). We conclude that in a high-risk population, the presence of microcephaly implies developmental impairment, though neither the absolute HC measurement nor the corrected HC centile is predictive. Coexisting epilepsy in this context appears to worsen developmental outcome.