A method and apparatus for the production of a pocketed spring unit by compressing and feeding a plurality of springs (42) into troughs (2A, 4A) or castellations in opposed conveyor belts (2,4), moving the springs (42) from the troughs (2A, 4A) or castellations to a position between upper and lower layers of fabric or other material (16A, 18A), step-wise advancing the material (16A, 18A) and the springs (42) in the direction of the output of the apparatus and welding together the lengths of fabric or other material (16A, 18A) at each step-wise advancement by a plurality of sequentially controlled welding anvils (10) so as to form a plurality of discrete pockets (46) each containing a spring (42).