The clinical, clinical laboratory, and viral aspects of 12 infants with acute, lower respiratory disease associated with group B, Coxsackie virus infection and/or isolation have been described. The prevalence of group B, Coxsackie virus infection was significantly greater among infants with lower respiratory disease than in infants without disease. Although a definite etiologic association could not be made because of the presence of concomitant infections with other viral agents, it was concluded that the group B, Coxsackie viruses might ultimately be added to the list of agents responsible for lower respiratory disease in infancy.