Hydrops fetalis is associated most commonly with erythroblastosis fetalis due to fetal-maternal incompatibility of the red cell Rh antigens. Many nonimmunologic disorders, including infections, homozygous alpha thalassemia, maternal diabetes mellitus, fetal malformations, the twin transfusion syndrome, and congenital nephrosis, may cause a similar syndrome. Although congenital syphilis has been mentioned as a cause of hydrops fetalis, reports of the association antedate the use of immunologic methods capable of detecting isoimmunization. We report here an hydropic infant with syphilis in whom there was no evidence of Coombs-positive hemolytic anemia, alpha thalassemia, or severe congenital malformations. See table in the PDF file See image in the PDF file