To study the characteristics and evolution of group B Streptococcus (GBS) late-onset diseases, over a period of 15years in 8hospitals the Barcelona area and analyze the possible impact of prophylactic measures for the prevention of early-onset neonatal infections. Retrospective review of all patients diagnosed with late-onset neonatal disease due to GBS from 1996 to 2010. A total of 143 patients were diagnosed. Of these, 51 were born in others hospitals. The overalll incidence was 0.42 per 1000 live births, varying between 0.14‰ in the year 2000 and 0.80‰ in 2009. A slight but sustained tendency of increased risk was observed over the years, 6.9% in the overall disease (with no statistical significance). Sepsis/bacteremia was detected in 63.6% of the newborns, meningitis in 32.8%, and arthritis/osteomyelitis in 3.5%. In cases with known obstetrics dates, 53% of mothers had been colonized by GBS during pregnancy, 53.8% received intrapartum antibiotic prophylaxis, and 41.2% had some obstetric risk factors, particularly premature birth in 35.9%. There was a 2.8% mortality rate in the neonates, and predominant serotypes were III and Ia. The incidence of GBS late-onset disease has not decreased despite the control practices of early-onset disease, and possibility of this appearing must be taken into account.