An infant girl acquired syphilis after exchange transfusion with fresh whole blood in 1977 in Rotterdam. She showed typical features of early infectious syphilis three and a half months after the transfusion. The parents had no histories or clinical or serologic signs indicative of syphilis. Although the blood donor had negative serologic tests for syphilis shortly before giving the blood, later examination indicated that he must have become infected with Treponema pallidum shortly before donation of the blood used in the transfusion of the infant.