We present 7 patients with a typical symptomatology of immotile cilia syndrome, three of them with complete situs inversus. Nasal mucociliary transport was studied by sero-albumin marked with technetium 99m. In all cases there was an absence of transport. The ultrastructure of the nasal cilia was studied. The findings were: In four cases alterations in the dynein arms, in three cases alterations in the central and peripheral microtubules associated por not to the defects in the dynein arms, and in one cases absence of cilia were observed. The ciliary complexes were common to all cases.