We reviewed the perinatal mortality due to group B streptococcal infection over a three-year period at a tertiary center. In 6 of 16 perinatal deaths due to group B Streptococcus, representing a range of gestational ages, infection occurred with the membranes intact. A review of reports from the obstetric and pediatric literature revealed that 10-50% of group B streptococcal infections occur in this manner. Several investigators of both animals and humans have demonstrated the pathophysiology of an ascending transamniotic infection. The current series emphasized this mode of infection in group B streptococcal disease.