In six experiments 43 castrated male conventional pigs weighing 25-41 kg were catheterised by inserting a cannula via the jugular vein into the cranal caval vein. The catheters were taped to the spinal neck region where the tap stops were located. Antimicrobial agents were not applied. One pig died 32 hour after surgery from Porcine Stress Syndrome. The catheters remained patent for at least nine days in 38 of the remaining 42 animals (90%). In two animals the catheter by mistake was not inserted into the jugular vein. Two animals got catheters with a one-way blockage four days after surgery. In these animals autopsy revealed thrombosis and phlebitis of the occluded vein and a valve-like thrombus at the tip of the catheters. In seven of the 43 pigs the effects of anaesthesia, surgery and catherisation were followed using rectal temperature and haematological and some blood biochemical parameters for nine days after the surgery. It is concluded that this catheterisation technique, without application of antimicrobial agents, can be used well for experimental infections and pharmacokinetic studies.