A reclosable fastener (10) comprising a male/female closure between a pair of opposed base members (18) has a single flange (16) for attachment of the closure to a web or film (34) on one only of the two base members. The fastener is attached initially to the film (34) by the single flange and then the fastener is additionally attached to the film (34) by heat and pressure applied in the region of attachment ribs (30) on the base members.