Umbilical cord ulceration is a serious complication of fetal intestinal atresia. To elucidate the relationship between fetal intestinal atresia and umbilical cord ulceration grade, we pathologically examined umbilical cords in 15 duodenal and 5 jejunal atresia cases and 28 control cases. Microscopic examination of the umbilical cords of patients with intestinal atresia revealed high-grade ulceration and a significant increase in macrophage numbers (P = 0.0087). Transudation of red blood cells was not associated with any specific clinical diagnosis, but was seen in all high-grade ulceration cases. It is suggested that clinical symptoms become apparent following gradual pathological changes.