There is an increasing interest in the physiology and pathology of the umbilical cord because it is recognized as an important source of placental and, consequently, fetal problems. During the postmortem examination of a severely macerated 13-week-old fetus, a split umbilical cord was noted. This rare finding was seen in the middle segment of the cord, the fetal and placental ends both being normal. The pathogenesis of this lesion is not fully understood, and it is possible that it results through focal degeneration of previously formed Wharton's jelly or secondary loss of Wharton's jelly due to incomplete fusion or hypoplasia of the amniotic covering. Whatever the pathogenesis, it is assumed that an umbilical vessel devoid of its protective Wharton's jelly is more prone to compression and thrombosis with all its deleterious effects. Death in this case was probably associated with the congenital heart defect also presented by the fetus. The rarity of this lesion is probably explained by the fact that it represents the end of the spectrum of longitudinal deficiency of Wharton's jelly, a relatively common finding.