Abstract: The present invention is a disposable diaper having an insert piece located transversely across at least one of the waist contacting ends of the diaper between the backing and the cover sheets. This piece overlies the filler pad between the pad and skin contacting cover sheet and serves to prevent liquid leakage from the pad in the waist zones. The insert pieces are made from a heat shrinkable elastomeric material of the type that is heat unstable and relatively inelastic in its unshrunk form and stable and relatively elastic in its heat shrunk. The ends of the insert pieces adjacent the waist margins are heat shrunk to provide an elasticized waist on the diaper which further serves to prevent leakage in this area.