Disruption of spatial and temporal patterns of gene expression in cells of the developing brain could result in abnormal development. We report that briefly exposing neonatal rats to a moderate dose of ethanol on postnatal days 5 through 7 caused a large, specific increase in glial fibrillary acidic protein (GFAP) mRNA and GFAP. Astrocytes of the cerebral cortex were apparently more sensitive to this effect of ethanol than astrocytes in several other brain regions. As a first step in the characterization of an vitro model of ethanol's effect on GFAP gene expression, ethanol was added to the media of primary cultures of cortical astrocytes in a pattern of exposure and at concentrations equal to pups' peak blood levels. This resulted in an increase in GFAP mRNA whose magnitude and specificity mirrored that observed in the animal model. Together, these results suggest that even brief exposure to ethanol can alter gene expression in astrocytes, and forms the foundation for further characterization of an in vitro model that may be used to determine the mechanism of this effect.