Prospective randomised study was conducted over a 24 months period in a cardiac surgical intensive care unit to determine the incidence of infection associated with multilumen venous catheters. The influence of various factors including fever, peripheral blood culture, catheter site, catheter usage for monitoring central venous pressure and/inotrope therapy on infection rates were statistically evaluated. A total of 100 catheters submitted to the Microbiology laboratory were bacteriologically examined. Forty-nine of these were inserted into upper body sites, and 51 were inserted into the femoral vein. Twenty-one were triple-lumen catheters. Catheters were removed when a central line was no longer necessary. Catheter tips were cultured by semiquantitative technique for aerobic and anaerobic bacteria. Bacteremia occurred in 3% of catheter insertions; (Enterococcus faecalis, one; Enterobacter spp. One; Acinetobacter spp., one); and catheter colonisation developed in 24%. Neither catheter colonisation nor catheter related infection were associated with any of the risk factors evaluated. Our data indicates that central venous catheters are safe to use in our patients. The inability to identify "risk factors" for catheter infection emphasise the need to maintain a high index of suspicion.