Behaviors mediated by the hippocampus have long been known to be sensitive to the acute, chronic, and prenatal effects of ethanol. It has recently become clear that hippocampal function is uniquely responsive to ethanol during periadolescent development, and that alcohol affects behavior and brain function differently in adolescents and adults. We have used behavioral techniques, as well as extracellular and whole-cell electrophysiological techniques, to assess the effects of acute and chronic ethanol exposure on hippocampal function during adolescence and adulthood. Our results are consistent with the view that the hippocampus is more sensitive to the acute effects of ethanol during adolescence and may be more susceptible to the neurotoxic effects of ethanol during this developmental period. Studies of this type have yielded valuable information for prevention, education, and public policy efforts related to underage drinking.