Two types of hernia appear to exist, a direct, cogenital type and an oblique indirect, acquired type. The congenital type will, in almost all instances, disappear by the age of three years, regardless of its size. It is unlikely that the indirect type of hernia will disappear; on the contrary, it is more likely to progress and become larger. It will, therefore, most probably require surgical repair. It is rarely possible to distinguich the two types at clinical examination, unless the hernia is quite large, but persistence after three years favors the oblique type, as does also marked downward displacement of the umbilicus with a clinical appearance of herniation descending from above. Since strangulation is a rarity in congenital umbilical hernia, operation is not warranted until the age of three years. Thereafer, the hernia is unlikely to disappear on its own. It is postulated that the wide variations in reported incidence, as compared with the figures in this study, may be ascribed to methods of patient selection. There was clear evidence of hernia in all instances in the present series; other workers have used less rigid criteria, for example, a defect admitting the finger was regarded as diagnostic of an umbilical hernia.