New neurons are continuously generated in discrete regions of the adult brain. In the hippocampus, newly generated cells undergo a step-wise progression of maturation that is regulated at multiple stages by a variety of physiological and pathological stimuli. Neural progenitors and newborn neurons initially receive exclusively GABAergic synaptic input, and accumulating evidence suggests that depolarizing actions of GABA contribute to activity-dependent regulation. Here we provide a brief overview of GABAergic signalling to newborn neurons in the hippocampus and describe how it regulates adult neurogenesis. © 2008 The Authors. Journal compilation © 2008 The Physiological Society.