Group B streptococcal (GBS) infections are the leading cause of bacterial disease and death among newborns in the United States and an important cause of morbidity among peripartum women and nonpregnant adults with chronic medical conditions. Disease in infants usually presents as sepsis, pneumonia or meningitis but also may include cellulitis or osteomyelitis. In 1990, GBS infections caused an estimated 7600 serious illnesses and 310 deaths among U.S. infants aged < or = 90 days; infections among infants aged < 7 days (i.e., early-onset disease) accounted for approximately 80% of these illnesses. To determine the incidence of GBS disease during 1993-1995, CDC conducted surveillance for this disease in an aggregate population of 12.5 million persons with 190,000 annual live-born infants. This report summarizes the findings of surveillance in this population, which indicate that a statistically significant decline in the incidence of early-onset GBS disease occurred in some surveillance areas.