THE PURPOSE of this study is to determine the incidence of chorioretinitis in children with congenital syphilis, especially with interstitial keratitis; to compare our findings with the well-known classification of Sidler-Huguenin; to discuss the frequency and diagnostic significance of perivasculitis in the eyegrounds of patients with congenital syphilis, points which we believe have not been sufficiently stressed, and to discuss the differential diagnosis of the retinitis pigmentosa type of syphilitic chorioretinitis and primary pigmentary degeneration of the retina. Although the incidence of congenital syphilis in the United States is decreasing and a syphilitic infant is rapidly becoming an anachronism,1chorioretinitis of congenital syphilis is still of importance, considering that in its atrophic stage it exists throughout the patient's life. Its diagnostic importance becomes apparent. The younger generation of ophthalmologists have less opportunity of seeing chorioretinitis of congenital syphilis, and, in contrast to the older literature, many modern texts do