Retrospectively, morbidity and mortality of neonatal early onset group B streptococcal (GBS) infection were established. Risk factors and prognostic factors were determined. Between 1985 and 1993, 78 patients with early onset GBS disease were identified. The overall mortality rate was 23%. In 60 of 73 cases (82%) at least one of the investigated risk factors was present. Low birth weight was not an independent risk factor. Outcome of 44 of 60 survivors (73%) at the age of at least one year was obtained. Almost 30% of them had sequelae. The most important were spastic disorders and delayed psychomotor development. In 42% of patients with symptoms of GBS-infection within six hours after birth sequelae occurred. There were no sequelae among patients with symptoms after 6 hours. All 9 severely brain damaged infants showed symptoms shortly after birth. Mortality and adverse outcome rate were higher in infants with low gestational age or low 5 minute Apgar scores. Early treatment resulted in less mortality, but not in less sequelae. GBS-sepsis still causes significant mortality and leaves a substantial number of survivors damaged. Alertness to GBS-infection, even in the absence of risk factors, remains crucial for early treatment and good outcome.