The chemokine fractalkine/CX3CL1 and its receptor CX3CR1 are constitutively expressed in the nervous system where they modulate neural transmission and neuroprotection. The strategic localization of CX3CR1 on microglia and in vitro studies suggested that the neurotrophic and neuromodulatory actions of CX3CL1 are indirect, requiring soluble factors released by microglial cells. Among these, adenosine plays a role, being released from CX3CL1-stimulated microglia and acting on different adenosine receptors (ARs). The involvement of astrocytes and ARs on the different activities of CX3CL1 will be discussed. Neuroprotection has been investigated with in vitro models of excitotoxicity on hippocampal and cortical neuronal and glial cultures and, in vivo, in a model of permanent MCAO in rats and mice. Neuromodulation has been investigated in hippocampal primary cultures and acute slices. For both studies, either pharmacological tools (specific AR antagonists and agonists, degrading enzymes like ADA or transporters inhibitors) or specific AR-deficient mice were used. Evidence are presented for a neuroprotective activity of CX3CL1 both in vitro and in vivo models of neurotoxicity mediated by microglia, astrocytes and adenosine through A1R, and for a neuromodulatory activity on glutamatergic transmission mainly mediated by A3R. We provide evidence that adenosine is an endogenous mediator involved in the neuroprotective and neuromodulatory activities of CX3CL1 in vitro and in vivo, with mechanisms requiring the cross talk between microglia and astrocytes.