The present invention is directed to delamination-resistant ultrasonic sealant films for packaging food, medical and/or pharmaceutical products having seals formed by ultrasonic sealing methods. The films according to the present invention have at least a sealant layer comprising a first propylene-ethylene copolymer and a second propylene-ethylene copolymer, a tie layer comprising at least one of the first or second propylene-ethylene copolymers of the sealant layer, and a barrier layer adjacent to the tie layer. The films according to the present invention may be used in aseptic, hot-fill and/or retort packaging applications.