A method and apparatus for the production of a pocketed spring unit, the method comprising the steps of compressing and feeding a plurality of springs (42) into troughs (2A, 4A) or castellations in opposed conveyor belts (2, 4), moving said springs (42) from said troughs (2A, 4A) or castellations to a position between upper and lower layers of fabric or other material (16A, 18A), step-wise advancing said material (16A, 18A) and said springs (42) in the direction of the output of the apparatus and welding together said 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). Apparatus for carrying out the method is disclosed.