Tissue vascularisation is a highly coordinated process requiring angiogenesis, arteriovenous differentiation and the patterning of the vascular network, but the signals responsible for its control, which come from neighbouring tissues, are largely unknown. On p. 941, Mukouyama and co-workers provide the first in vivo evidence that VEGF (vascular endothelial growth factor) from the peripheral nervous system is necessary for arteriogenesis. By using transgenic mice in which Vegfa is conditionally deleted in sensory neurons, motoneurons and/or Schwann cells,the researchers show that nerve-derived VEGFA is required for arterial differentiation in the skin of embryonic mouse limbs. Endothelial expression of neuropilin 1 (NRP1) - a VEGF-induced artery-specific VEGF co-receptor - is also required, suggesting that a NRP1-mediated positive feedback loop may promote arteriogenesis. Surprisingly, nerve-vessel alignment is normal in these mutants, indicating that this alignment, which subsequently patterns the vasculature, must be mediated by residual levels of VEGFA or by another nerve-derived signal.