In this prospective study we analysed 336 consecutive central venous catheters in neonates less than 3500 g. A protocol standardizing the technique of insertion, the care of the catheter, the preparation of solutions and weekly bacteriological screening was applied to all catheter insertions. Mechanical complications were observed in 15 (6%), catheter dislodgement (5%), obstruction (8%), perforation (2%) and caval vein thrombosis (0.6%). Routine bacteriological cultures of feeding solutions and infusion devices showed a contamination rate of 3.5% and 2%. Skin swab and catheter tip cultures after catheter removal demonstrated positive results in 6% and 4.7%, but catheter related sepsis occurred in only 2.3%. Staphylococcus epidermidis was found in 81 % of all positive bacterial cultures. Four point seven per cent of catheters were removed for suspected infection though only one third of them produced a bacteriological growth. We conclude that the risk of mechanical complications and contamination of central venous catheters in neonates can be minimized by the use of a standardized protocol.