Recently, new broad spectrum carbapenem has been investigated on a world-wide scale for the treatment of moderate to severe infections. In the neonatal intensive care units the extensive use of third generation cephalosporins for therapy of neonatal sepsis may lead to rapid emergence of multiresistant gram-negative organisms. We report the use of meropenem in 35 infants with severe infections due to Acinetobacter baumanii and Klebsiella pneumoniae. All gram negative bacteria were resistant to ampicillin, amoxicillin, ticarcilin, cefazoline, cefotaxime, ceftazidime, ceftriaxone and aminoglycosides. Eighty two percent of the cases (29/35) were born prematurely. Assisted ventilation was needed in 85.7% (30/35). All infants deteriorated during their conventional treatment and were changed to meropenem monotherapy. Six percent (2/35) died. The incidence of drug-related adverse events (mostly a slight increase in liver enzymes) was 8.5%. No adverse effects such as diarrhea, vomiting, rash, glossitis, oral or diaper area moniliasis, thrombocytosis, thrombocytopenia, eosinophilia and seizures were observed. At the end of therapy, overall satisfactory clinical and bacterial response was obtained in 33/35 (94.3%) of the newborns treated with meropenem. Clinical and bacterial response rates for meropenem were 100% for sepsis and 87.5% for nosocomial pneumonia. This report suggests that meropenem may be a useful antimicrobial agent in neonatal infections caused by multiresistant gram negative bacilli. Further studies are needed to confirm these results: Meropenem, newborn, sepsis and nosocomial infection.