The insertion and the permanence of central venous catheters (CVC) represent potential sources of infection contracted in hospital. The evaluation of the risk of CVC-associated infections was evaluated in a retrospective study during the period 2007-2010 in a Hospital of Central Italy. A total of 514 CVC were collected and examined by microbiological techniques and, among the examined patients, 450 CVC blood cultures were collected. Cultures were performed collecting a portion of 5-6 cm of intravenous catheters in liquid medium and spread on selective media for Gram-positive and Gram-negative bacteria and yeasts; blood specimens were obtained through peripheral venous punctures and analyzed by a commercial automated system. 308/514 (59.90%) samples were positive to the microbiological culture. Staphylococcus aureus, S. epidermidis and other coagulase negative Staphylococci (CNS) were the prevalent Gram-positive bacteria. Among Gram-negative bacteria, Enterobacteriaceae and Pseudomonaceae were the main bacteria isolated. A higher prevalence of Gram-positive bacteria was observed in Neonatal Pathology (90.90%). The Intensive Care Unit (ICU) showed 73.10% of positive cultures with 54.12% of Gram-positive isolates. Among positive blood cultures (38%), Gram-positive bacteria were the main bacteria isolated. The high prevalence of catheter-related infections requires accurate surveillance and the assumption of preventive measures in particular during catheter insertion.