BACKGROUND Central venous catheters (CVCs) facilitate venous access, allowing the intravenous administration of complex drug treatments, blood products and nutritional support, without the trauma associated with repeated venepuncture. However, CVCs are associated with a risk of infection. Some studies have indicated that the type of dressing used with them may affect the risk of infection. Gauze and tape, transparent polyurethane film dressings such as Tegaderm® and Opsite®, and highly vapour-permeable transparent polyurethane film dressings such as Opsite IV3000®, are the most common types of dressing used to secure CVCs. Currently, it is not clear which type of dressing is the most appropriate. OBJECTIVE To compare gauze and tape with transparent polyurethane CVC dressings in terms of catheter-related infection, catheter security, tolerance to dressing material and dressing condition in hospitalised adults and children. METHODS For this third update, we searched The Cochrane Wounds Group Specialised Register (10 May 2011); The Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2011, Issue 2), Ovid MEDLINE (1950 to April Week 4 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, May 11, 2011); Ovid EMBASE (1980 to 2011 Week 18); and EBSCO CINAHL (1982 to 6 May 2011). METHODS All randomised controlled trials (RCTs) evaluating the effects of dressing type (e.g. gauze and tape versus transparent polyurethane dressings) on CVC-related infection, catheter security, tolerance to dressing material and dressing condition in hospitalised patients. METHODS Two review authors independently assessed trial quality and extracted data. We contacted study authors for missing information. RESULTS Six studies were included in earlier versions of the review. In this update two of the previously included papers have been excluded and two new trials have been added. Of these six trials, four compared gauze and tape with transparent polyurethane dressings (total participants = 337) and two compared different transparent polyurethane dressings (total participants = 126). Catheter-related bloodstream infection was higher in the transparent polyurethane group when compared with gauze and tape; OR 4.19 (95%CI 1.02 to 17.23) however these small trials were at risk of bias so this evidence is graded low quality. There was no evidence of a difference between highly permeable polyurethane dressings and other polyurethane dressings in the prevention of catheter-related bloodstream infection (low quality evidence). No other significant differences were found. CONCLUSIONS We found a four-fold increase in the rate of catheter related blood stream infection when a polyurethane dressing was used to secure the central venous catheter however this research was at risk of bias and the confidence intervals were wide indicating high uncertainty around this estimate; so the true effect could be as small as 2% or as high as 17-fold. More, better quality research is needed regarding the relative effects of gauze and tape versus polyurethane dressings for central venous catheter sites.