Enterobacteriaceae are now the predominant pathogens isolated in bloodstream infections complicating orthotopic liver transplantation (OLT). We conducted a retrospective cohort study of patients who underwent OLT in a University hospital between 01/01/1997 and 31/03/2003 to investigate the risk factors of Enterobacteriaceae bacteremia (EB) after OLT. EB was defined as the isolation of an Enterobacteriaceae species from at least one blood culture within 3 months following OLT. Pre-, per- and postoperative variables were collected from the medical records and analyzed in relation to EB. Forty (12.5%) of the 320 patients developed EB. The origin of EB was abdominal in 32% of the patients, urinary in 18%, pulmonary in 10%, and primary in the remaining 40% of the patients. Two-thirds of EB occurred within 1 month following OLT. The main pathogens were Escherichia coli (42%), Enterobacter cloacae (17%) and Klebsiella pneumoniae (17%). Susceptibility rates varied from 82.5% for ciprofloxacin to 95% for amikacin. Fourteen patients (35%) with EB died. Variables significantly associated with EB after multivariate analysis were a MELD score >20 (OR: 2.79 [1.24-6.30], P=0.013), transplantation for posthepatitic B (OR: 4.47 [1.67-11.98], P=0.03) or posthepatitic C (OR: 3.79 [1.59-9.01], P=0.03) cirrhosis, a positive bile culture (OR: 3.47 [1.19-10.13], P=0.023) and return to surgery (including retransplantation) (OR: 2.72 [1.32-5.58], P=0.006). EB is a frequent and severe complication following OLT. Patients grafted for a posthepatitic cirrhosis, with a severe pretransplantation status, with a positive bile culture and those undergoing reoperation have a high risk of developing EB.