• It has frequently been cited that a delay in back closure of beyond age 48 hours in newborns with myelomeningocele is associated with an increased risk of ventriculitis. It has been suggested that antibiotic therapy prior to surgery might minimize this risk. We reviewed our experience with ventriculitis in newborns with myelomeningocele and its relationship to antibiotic usage and time of back closure. Of 186 newborns, ventriculitis developed in 13 (7%), and there was no observed difference by time of back closure, clinical severity of infant at birth, status of myelomeningocele sac at birth, or type of delivery. There was a significant association between antibiotic usage and ventriculitis among the infants with delayed surgery, of which only one (1%) of 73 receiving broad-spectrum antibiotic prophylactic therapy developed ventriculitis compared with five (19%) of the 27 who did not receive antibiotics. Our data support the suggestion that antibiotic treatment is effective in minimizing the risk of ventriculitis among infants with myelomeningocele undergoing surgery after 48 hours of age.