The aims of this study were to explore the incidence of neonatal bacteraemia and identify the risk factors among neonatal intensive care unit (NICU) patients. The study included 3339 neonates admitted to the NICU of Ioannina University Hospital, North-Western Greece, during the 10-y period 1989-98. Logistic regression was used to assess the contribution of different risk factors to bacteraemia. A diagnosis of bacteraemia was made in 90 neonates (2.7%), 10 of whom (11%) died. Gram-negative bacilli, coagulase-negative Staphylococci and Streptococci were the most common pathogens: 42%, 34% and 17%, respectively. Premature rupture of membranes was the main risk factor for early-onset sepsis (relative risk 6.28) and respiratory distress syndrome was the main risk factor for late-onset sepsis (relative risk 5.70). The relative size of neonates for their gestational age did not appear to influence the risk of infection. Case fatality was higher for early- than for late-onset sepsis (relative risk 6.59). In conclusion, certain conditions were confirmed to predispose patients to neonatal bacteraemia; neonatal morbidity and mortality can be reduced by intervening to control these predisposing factors.