We report a case that presents clear evidence of an intrauterine infection of twin fetuses with an enterovirus. The mother had signs and symptoms of chorioamniotitis at 34 weeks' gestation. Coxsackie virus, group B type 1 (CVB1), was cultured from amniotic fluid obtained by transabdominal amniocentesis when the membranes of both fetuses were still intact. Delivery occurred vaginally approximately 24 hours later, following spontaneous rupture of membranes. At birth, both twins showed signs of sepsis. Postpartum, CVB1 was recovered from the mother's cervix, and the newborns' cerebrospinal fluid, nasopharyngeal, and rectal swabs. The present significance of this case is discussed.