Infection of vascular catheters is one of the leading causes of nosocomial bacteremia in the critically ill patient. Most catheter-associated infections result from exogenous microbial contamination of the catheter at the time of insertion or during use and are endemic. Prevention of catheter-associated infection is based on measures designed to eliminate the potential for microbial contamination of the skin at the catheter insertion site, the catheter hub, tubing connectors, and any inline devices that may be present. Development and implementation of catheter-care protocols for use in the ICU should be effective in preventing catheter infections. The diagnosis of catheter infections is difficult, as there are few signs or symptoms that are specific for an infected catheter. Catheter infection should be suspected in patients who develop fever, chills, and leukocytosis with no other apparent site of infection.