In a method and apparatus for manufacturing two-ply agricultural storage bags, two supplies (36, 38) of flexible tubular materials are positioned on opposite sides of feed wheels (26) mounted on a generally cylindrical frame structure (24). The inner material (36a) from the first supply (36) extends through the frame (24) and outwardly around the feed wheels (26). The outer material (38a) from the second supply (38) extends around the feedwheels (26) in surrounding engagement over the inner material (36a). Actuation of the feedwheels (26) effects simultaneous advancement of the materials (36a, 38a) around the frame (24) so that a bag can be collected at the lower end of the frame.