Twenty-seven ill neonates with enterovirus infections were studied to learn if enterovirus infection can be distinguished from neonatal sepsis. Enterovirus infection was associated with the summer-fall season (93%), recent maternal illness (59%), absence of other perinatal problems (81%), and findings of fever (93%), viral meningitis (62%), diarrhea (81%), and rash (41%). Four children developed thrombocytopenia and three necrotizing enterocolitis. Three children died, all with Coxsackie B virus infections that likely were acquired in utero. Although no single feature is pathognomonic, this constellation of epidemiologic and clinical findings, coupled with negative bacterial cultures, should suggest the possibility of neonatal enterovirus infection.