Group A Streptococcus (GAS) was a major cause of neonatal sepsis before the antibiotic era, but its incidence declined with the availability of antibiotics and improved perinatal infection prevention measures. It is now a rare cause of neonatal sepsis. Streptococcus pyogenes sepsis in early infancy can be associated with a variety of complications. Complicated pneumonia (pneumonia with effusion, empyema, or necrosis) has been reported in 3 bacteremic infants with early-onset sepsis. This is the first report of complicated pneumonia in late-onset sepsis due to S pyogenes.Although an unusual cause of sepsis in the first months of life, GAS remains an important pathogen for the delivering mother and newborn infant. As this case illustrates, complications of GAS late-onset sepsis, including complicated pneumonia, can develop. This pathogen should be considered in the evaluation of the ill newborn and young infant.