Inflammation can promote axon regeneration. For example, proinflammatory cytokines can induce retinal ganglion cells to regenerate after optic nerve injury; however, the cell types and molecular mechanisms involved in this process are not well understood. Here, the authors showed that effective axon regeneration after optic nerve injury in mice required both neutrophils — which rapidly entered the site of injury-induced inflammation — and the atypical growth factor oncomodulin that they released. This indicates that neutrophils, which are components of the innate immune system, can promote nerve regeneration in the CNS.