Abstract: An underplate for use in the printing of a tubular fabric, which is made in the shape of a polygonal tube that can be transformed in shape along the lines of the angles; and a method for printing a tubular fabric conprising: (1) inserting the underplate into the tubular fabric; (2) making the fabric flat along appropriate lines of angles in said polygonal tube; (3) doing printing on or near the center of the front surface of the fabric, corresponding to the front surface of said flat shape; (4) turning over the fabric with said flat shape; doing printing in the same way on or near the center of the back surface of the fabric, corresponding to the back surface of said flat shape; (5) bringing back said flat shape to its original shape; (6) making the fabric flat again along different lines of angles in said polygonal tube, in such a manner that a different flat shape is formed from the polygonal tube, with the above-mentioned two regions of the fabric that have been printed at the sides of this second flat sha