Prior to initial contact formation, intrinsic developmental programs and external guidance cues are responsible for guiding growing axons into their target field.Sensory input is generally thought to be necessary for refining and consolidating neuronal connections in developing neuronal networks.We here report that cortical callosal axons in the somatosensory cortex absolutely require sensory input for their target selection in the contralateral cortex.Eliminating sensory input to either hemisphere by unilateral transection of the infraorbital nerve (ION) prevents target selection of callosal axons in the contralateral cortex.Strikingly, blocking sensory input bilaterally, by simultaneously transecting both IONs, callosal projections are largely restored.In contrast, non-simultaneous bilateral ION transection has the same effect as unilateral transection, regardless of which side is lesioned first.Our data demonstrate the critical role of somatosensory input in guiding callosal axons into their target cortical territory.