To explore the functional consequences of adult neurogenesis in the mouse olfactory bulb, we investigated plasticity at glutamatergic synapses onto GABAergic interneurons. We found that one subset of excitatory synapses onto adult-born granule cells showed long-term potentiation shortly after their arrival in the bulb. This property faded as the newborn neurons matured. These results indicate that recently generated adult-born olfactory interneurons undergo different experience-dependent synaptic modifications compared with their pre-existing mature neighbors and provide a possible substrate for adult neurogenesis-dependent olfactory learning.