Abstract: The invention relates to a truncation apparatus and a process of truncating tubes. The truncation apparatus includes a mandrel, a means for advancing the tube to be truncated along the mandrel, at least one knife positioned in proximity to the free end of the mandrel, a slide moveably mounted on the mandrel and an exterior abutment whose distance with respect to the knife is adjustable, in addition to at least one reference system which is longitudinally adjustable adjacent the mandrel and defines predetermined and adjustable lengths between the front end of slide and the knife, and is provided with means to stop the longitudinal displacement of the slide in a manner so as to define a selected length for the last truncated portion of the tube. A method for truncating tubes wherein a length of tube is positioned on a mandrel and cut into at least a first section including one of the end edges of the tube and a last section including the other end edge of the tube.