Development of the vertebrate CNS begins during neurulation when the neural plate gives rise to the neural tube. During neurulation, the different regions of the CNS can be identified in part by the appearance of flexures in the walls of the neural tube. Here we report the isolation and characterization of F-cadherin; a novel member of the cadherin family of cell adhesion molecules, which is expressed at flexures in the neural tube of Xenopus embryos. We show that F-cadherin is first expressed at neural plate stages, that its expression is altered when patterning of the neural tube is perturbed, and that its expression marks boundaries in the neural tube where cell mixing is restricted. These observations suggest that F-cadherin contributes to the regionalization of the neural tube perhaps by mediating differential cell adhesion.