Children who are admitted to hospital for intensive care often need to have medicines given directly into their veins, through a small plastic tube called a central venous catheter (CVC). CVCs avoid the need for repeated injections, but their disadvantage is an increased risk of bloodstream infection (BSI), which can result in prolonged treatment and time in hospital. In adults, CVCs coated with medicine to kill bacteria (antibiotics) or prevent clots (heparin) help reduce the risk of BSI. However, we do not know if coating the much narrower CVCs used for children would work in the same way. The only way to find out which type of CVC (standard non-coated, antibiotic coated or heparin coated) works best was to carry out a randomised controlled trial. Children aged < 16 years who needed a CVC for intensive care treatment participated within 14 hospitals in England. Consent was provided for all participants in the trial. Each child had an equal chance of receiving one of the three CVC types. Bloodstream infection occurred in 4% of children with standard CVCs and 2% of those with impregnated CVCs. Rates of BSI were lowest in the antibiotic CVC group (1%) but these children had slightly higher health-care costs for the 6 months after trial participation. Although doubt remains whether or not antibiotic CVCs would result in cost savings for the NHS in England, our results suggest that using antibiotic CVCs could help reduce BSI rates for children in intensive care.