Apparatus and method for filling bags wherein the bags are gusseted and extend from a first end to a second end. The gussets are optionally pulled outwardly out of the second bag end by means of a spreader device to provide a large filling mouth. The bag is attached to a filling spout by its opened second end where it is filled at least in part before the second end of the bag is closed by means of a closing device by way of at least one closing seam.