The central corneal thickness was measured in 53 patients with osteogenesis imperfecta. The average thickness was found to be 0.443 ± 0.003 (SEM) mm. This value was significantly lower than the central corneal thickness in 35 patients with otosclerosis (0.515 ± 0.004 mm) and in 35 sex- and age-matched normal control subjects (0.522 ± 0.004 mm). No difference in corneal thickness between otosclerosis and controls was observed. Measurements of the central corneal thickness may be of great value in the diagnosis of osteogenesis imperfec