BACKGROUND There is a wide variation of perineural catheter (PNC) colonization rates in the literature. The impact of skin disinfection on PNC colonization and inflammation is not clear. The objective of this prospective, randomized clinical study was to investigate the influence of alcoholic skin disinfection before PNC removal on the detection of bacteria on PNC. METHODS Two hundred patients receiving a PNC for orthopaedic surgery were random- ized to receive (with-group) or not (without-group) a skin disinfection with a sprayed alcoholic solution before removal of the PNC. Bacterial colonization and contamination of the PNC and clinical signs of inflammation and infection of the PNC insertion site were evaluated. Skin disinfection with a sprayed alcoholic solution and sterile removal of the distal and subcutaneous part of the PNC was performed after 72h or earlier if signs of infection occurred with semiquantitative culture and enrichment culture of both parts. RESULTS Alcoholic skin disinfection before PNC removal significantly reduced bacterial colonization with a reduction from 28% to 14% and from 32% to 17% for the tip and the subcutaneous part of the PNC, respectively (p < 0.05). Clinical signs of inflammation at the PNC insertion site were similar (73%) in the two groups. The detection of colonization in 54 (27%) out of 200 PNC did not correlate with clinical signs of inflammation independently of the number of bacteria isolated. Redness was noted in 71 % and 68 % of patients in the WITHOUT- and WITH-alcoholic skin disinfection-group respectively. Local pain on pressure was present in 28% and 19% in the without- and with-group respectively. CONCLUSIONS Alcoholic skin disinfection before PNC removal reduced the detection of PNC colonisation by 50%. There was no correlation between clinical signs of inflammation and PNC colonization.