The ciliated mechanosensory cells of the inner ear, the hair cells, are uniquely adapted to their task detecting sound and balance information.However their formation is considered to be a simple modification of the prototypical epithelial cell: the primary cilium is transformed into a kinocilia, and actin-based microvilli are transformed into stereocilia.Previous studies have shown that protocadherin15 (PCHD15) is found on kinocilia where it forms kinociliary links with adjacent stereocilia.PCHD15 is found on kinocilium but not primary cilia, such as those found on supporting cells, indicating that the mechanisms that deploy PCHD15 to the kinocilia are unique.We find that the fibroblast growth factor receptor, FGFR1, also localizes to kinocilia, where it forms discrete signalosomes.These particles co-localize with members of the intraflagellar transport (IFT) machinery such as IFT88 and KIF3A, as well as PCHD15.Disruption of FGF signalling, causes a failure of the IFT machinery to enter the kinocilia and furthermore PCHD15 does not localize to the kinocilia.Furthermore, blocking FGFR1 signalling phenocopies a kinocilia-specific deletion of pchd15.We suggest that FGFR1signalling plays an important, non-transcriptional role in hair cell morphology by directing PCHD 15 localization to the kinocilla.