Mucociliary transport and ultrastructure of nasal cilia in a 13 year old boy with Kartagener's triad, were investigated. Mucociliary transport was significantly delayed (greater than 30 minutes). Electron microscopy showed cilia lacking radial spokes, eccentric central tubules, and a dislocation of one the outer doublets. Dynein arms were present. We consider the radial spoke defect as a distinct congenital anomaly which contributes to the pathogenesis of the "immotile cilia syndrome".