Children (358) from grades 1 through 3 in 2 elementary schools, were selected on the basis of normal hearing, normal intelligence, average socioeconomic background and absence of physical handicap. Patterns of swallowing, articulation of (1), (s-z), (r), and (ts-dz), and dental occlusion over a 2-yr. period. The data confirmed the presence of the tongue-thrust syndrome in the majority of the population studied. Maturation alone did not reduce the incidence appreciably.