The Morquio syndrome is characterized by a specific pattern of platyspondylia, corneal opacities, keratosulfate excretion in the urine, and dental abnormalities. Oral examinations were performed on twelve patients with the condition. The maxillary anterior teeth were widely spaced and flared. The posterior teeth were tapered and had pointed cusp tips. The enamel was of normal hardness, and in some patients the surface was pitted. In roentgenograms, the enamel was less than one fourth its normal thickness but was of normal radiodensity. The prevalence of caries may have been reduced. The hard palates were broad and flat. The dental abnormalities in the Morquio syndrome are of a type that is unique among the group of genetic mucopolysaccharidoses. Our findings therefore support the conjecture that the biochemical defect in this condition is different from that which occurs in the other mucopolysaccharidoses.