Two cases of definitive paraplegia following umbilical artery catheterization are reported. In both patients, the paraplegia can be attributed to a myelomalacia secondary to the thrombosis or embolization of the feeding arteries of the cord. The treatment by fibrinolytic agents was unsuccessful and the only therapeutic approach appears to be a preventive one. This prophylaxis would best be accomplished by limiting the indications and duration of umbilical artery catheterization.