peer reviewed ; Background: In the late 1990s, Belgium has reached the era of “group B streptococcal (GBS) prevention” and after 1996, some institutions, but not the majority, had implemented intrapartum antibioprophylaxis for GBS prevention. Concern exists that one unintended consequence of GBS prevention efforts through chemoprophylaxis may be an increase in the rate of serious neonatal infections due to Gram negative bacteria (GNB). To monitor trends, continued surveillance of neonatal sepsis is needed. Methods: On a weekly basis, laboratories of the Belgian sentinel network notified each case of neonatal bacteremia or meningitis occurring within 28 days after birth. We reviewed on a year-base data collected from 1991-2001 for early–onset diseases (EOD; < 5 days). Results: A yearly mean of 47 cases (24-90) were notified by 28 (16-35) laboratories. Overall GBS remained the leading cause and represented annually 37.9% (25-54.7%) of EOD and did not show significant change. It was followed by E.coli 11.4%, coagulase negative staphylococci (CNS) 11.9%, S.aureus 9.9%, Listeria sp 3.9%, S.pyogenes (GAS) 2.5%, S.pneumoniae 2.7%, H.influenzae 2.7% and others. During the decade, whereas a significant reduction in the rate of E.coli and other GNB EOD occurred (p <0.01), significant increases in the rate of EOD due to GAS (p <0.001), S.aureus (p <0.001), and CNS (p <0.01), were found. For CNS, we did not have data to distinguish definite or possible infections from contaminations. Conclusions: 1) During the last decade, GBS has remained the leading cause of neonatal EOD. 2) A decline in the rate of E.coli and other GNB infections occurred. 3) In the late 1990s, S.aureus and CNS were more frequently reported. 4) An increase in GAS occurrence was found 5) Potential change in pathogens overtime requires confirmation by ongoing surveillance.