Erythropoietin is a potent regulator of erythropoiesis. It acts via the specific membrane receptor (EpoR). Erythropoietin is also known to be present in the central nervous system, and its concentration and the expression of EpoR change during development, which raises the possibility that this modulator might be involved in the regulation of neuronal functions in the developing brain. The GABAergic system undergoes profound changes during development and is particularly susceptible to modulation by endogenous factors. Therefore, we decided to investigate the impact of Epo on GABAergic transmission in hippocampal neurons developing in vitro. An analysis of miniature IPSCs (mIPSCs) revealed that a long-term treatment with Epo (48 or 72 h) resulted in a major acceleration of the decaying phase of these currents while the amplitude and current frequency remained unchanged. Interestingly, this effect was restricted to the youngest considered age group (6-8 DIV), indicating that Epomediated modulation of mIPSCs depends on the developmental stage of the neurons. We conclude that Epo may exert a modulatory action on GABAergic transmission in developing neural networks.