Adult generated neurons in the dentate gyrus become functionally integrated into the existing hippocampal circuit by forming synapses with mature neurons. It is now well established that seizure activity increases neural proliferation, but only recently has the fate of seizure-induced newborn neurons been examined. An emerging consensus proposes that newborn neurons are highly sensitive to their environment, such that synaptic integration is profoundly altered following insults such as seizures. Whether these changes contribute to or counteract epileptogenesis is a subject of great interest because neurogenesis provides a potential target for therapeutic intervention. In this review, we summarize the current understanding of the functional integration of adult generated granule cells in the normal rodent hippocampus, and describe how this process can be altered during epileptogenesis. © 2008 International League Against Epilepsy.