Extrusion coating and lamination processes are integral for converting many of today’s high performance flexible packaging structures, most notably pouch structures. Extruding a coating or laminating a polyolefin or blends of polyolefins onto a substrate, such as paper or aluminum foil, to form a composite packaging structure is well known in the art. Depending upon the end use, such composite structures will also desirably have good adhesion, flexibility, barrier properties and heat resistance. For example, food storage pouches need sufficient adhesion strength to be handled during filling of the pouch, during preparation and storage and subsequent heat seal resistance during immersion in boiling water and subsequent handling. This study examines how the use of atmospheric plasma surface treatment technology compares to the use of corona as pretreatments in promoting seal strength of an extrusion-coated flexible packaging structure.