In adulthood, offspring with Fetal Alcohol Effects exhibit different responses to ethanol than nonexposed offspring; however, the majority of this research has utilized high levels of ethanol prenatally with resultant behavioural and/or physical anomalies. The present research focused on moderate prenatal ethanol exposure and subsequent challenge with low doses of ethanol. Following impregnation, female rats were exposed to between 3-4 g/kg of ethanol in a saccharin solution daily in a voluntary free-choice with water during one of each trimester or during all trimesters. There was a no-ethanol control group which received saccharin only as well as a group of foster dams who drank only water. At 30 days of age, male offspring were tested in an open-field after injection of either 1 g/kg ethanol or a comparable volume of saline. Rats exposed prenatally to ethanol in the second trimester showed enhanced locomotor activity. However, rats exposed prenatally to ethanol in either the first, third or during all trimesters showed no significant augmentation in activity. The results are discussed in terms of the adverse effects of moderate levels of prenatal ethanol exposure on fetal neurochemical development, specifically, the excitatory and inhibitory systems.