Abstract: A method is disclosed for producing heat exchange tubing for use in tube and shell heat exchangers hag proved heat exchange and proved fluid flow around the heat exchange tubes in which cylindrical tubing is deformed by pressure rollers to produce tubes having cylindrical ends and intermediate potions of elliptical cross section. These tubes may also be bent to U-shaped heat exchange tubes. The cylindrical end portions on one end are secured in a tube sheet, and the elliptical intermediate portions extend through baffle plates having openings sized according to TEMA standards. The assembly is secured a shell having inlet and outlet openings on the same side or opposite sides of the shell and a second be sheet fitted over the other cylindrical ends of the heat exchange tubes, dished headers are secured over each of the tube sheets providing an inlet/outlet header at one end and a fluid return header at the other end.