Abstract: A method of forming a soft, deformable tip at the distal end of an elongated, flexible catheter made from a thermoplastic or elastomeric material in which the tip portion is first heated to soften the plastic and, subsequently, a specially prepared forming tool is inserted into the lumen of the catheter at the distal end and advanced to the point where an annular protuberance of a predetermined outside diameter is forced into the lumen so as to stretch and shape the plastic to conform to the forming tool. The distal end is then cooled and the forming tool removed, leaving a soft, collapsible segment integrally formed at the distal end of the catheter.