Objective. - Central venous catheter (CVC) insertion is routinely performed in critically ill patients but causes mechanical, thrombotic, or infectious adverse events in 15% of cases. It should be possible to improve the benefit/risk ratio of central venous catheterization in intensive care unit. Data source. - We searched Pubmed using the terms: '' catheterization, central venous, peripheral, adverse effects ''; then '' thrombosis, phlebitis, thrombophlebitis, jugular vein, femoral vein, subclavian vein, pneumothorax, haemothorax, extravasation of diagnostic and therapeutic materials ''. We then discuss this with a panel of intensivists in a workshop. Data synthesis. - Few data are available oil the risk/benefit ratio of central vs. peripheral venous catheterization. In some cases (cardiac arrest, rapid fluid loading, parenteral nutrition) the choice is based on clear recommendations. In others (irritating drugs, pressure monitoring, peripheral access failure), the choice depends on medical and nurses daily evaluation. When CVC insertion is mandatory, it is important to implement the recommendations of the consensus conferences to prevent infectious and thrombotic complications. Mechanical complications should be improved by selecting the most appropriate insertion site, and, if Unsuccessful, switching to another operator before the complications occurs. Doppler-ultrasound guidance is recommended, but is limited by the cost and training of the technique. Conclusion. - Studies evaluating the risk/benefit ratio of CVCs versus peripheral catheters are needed to develop a venous-access strategy for ICU patients. When a CVC is mandatory, recent data are available to improve the risk/benefit ratio and can be used to build a decision algorithm. (c) 2005 Elsevier SAS. Tous droits reserves.