Abstract: A catheter positioning system comprises a guide catheter extension adapted to co-operate with a guide catheter, a catheter positioning device adapted to engage a catheter and guide the catheter within the guide catheter extension, wherein the guide catheter extension further comprises a plurality of engagement means for fixing the relative points of the guide catheter extension and the positioning device at any one of a number of positions over its length and a guide catheter extension capable of receiving a catheter, comprising a substantially rigid tubular section capable of sealing engagement within a compression fitting of the guide catheter.