Introduction: Intravascular catheters, which are among the indispensable procedures of medical practice, are the leading cause of nosocomial infections, particularly in intensive care units. In our study, we aimed to determine the rates of intravascular catheter-related infections, risk factors and causative microorganisms. Materials and Methods: Patients admitted to the Karadeniz Technical University Faculty of Medicine Hospital between October 2003- November 2004 were followed prospectively in terms of infections and risk factors associated with intravascular catheters. Results: A total of 770 intravascular catheters inserted in 434 patients were followed for 11.385 catheter days. Overall, 116 catheter-related infections (CRIs) were determined. The rate of CRI was 10.2, and the rate of CR-blood stream infection (BSI) was 6.4. In the multivariate analysis of risk factors affecting the development of CRI, independent factors causing an increase were found to be high Acute Physiology Assessment and Chronic Health Evaluation (APACHE) II scores (OR = 1.07, 95% CI = 1.02-1.13; p< 0.0005), prolongation of the duration of catheterization (OR = 1.03, 95% CI = 1.02-1.04; p< 0.0005), use of anti-pseudomonal penicillin before and during the catheterization (OR = 4.5, 95% CI = 1.85-10.96; p< 0.0005), use of quinolones (OR = 3.1, 95% CI = 1.04- 9.13; p= 0.038), use of the catheter for total parenteral nutrition purposes (OR = 3.9, 95% CI = 2.17-7.05; p< 0.0005) or for hemodialysis purposes (OR = 6.3, 95% CI = 3.28-11.96; p< 0.0005), insertion of the catheter under emergency conditions (OR = 5.02, 95% CI = 2.65-9.49; p< 0.0005), and insertion of the catheter by inexperienced healthcare staff (OR = 1.9, 95% CI = 1.10-3.35; p= 0.030). Maintenance of hand hygiene during the insertion of the catheter and taking the maximum barrier precautions reduced the rate of CRI by 87% and 58%, respectively (OR = 0.13, 95% CI = 0.07-0.24, p< 0.0005; OR = 0.42, 95% CI = 0.24-0.73; p< 0.0005, respectively). The causative microorganisms isolated in CRIs were gram-positive microorganisms in 69 (58.5%), gram-negative microorganisms in 41 (34.8%) and Candida spp. in 8 (6.8%) of the patients. Conclusion: Our study shows that taking certain precautions against risk factors including hand washing, higher level barrier precautions, and frequent manipulation will reduce the incidence of CRIs. Furthermore, hospital staff should be well informed about catheter insertion and care in conformity with the rules of antisepsis and about intravascular CRIs