One of the most prevalent of waste materials is Polyethylene Terephthalate (PET) which is used mainly to produce the drinking water bottles. In this research, the waste plastic bottles, which are normally made from PET was used to investigate the possibility of using this material as an additive in asphalt concrete mixtures. Six different proportions (w/w %) of Degradated Polyethylene Terephthalate (DPET) (2, 4, 6, 8, 10, and 12%) have been added to bitumen to prepare the specimens. The tests include Marshall Method of mix design and coating with asphalt. The results indicated that the mixture property modification increased as the content of (DPET) increases. This additive gives maximum flexibility and rigidity of the asphalt, according to ductility and penetration tests. Marshall Method gives better resistance against permanent deformations and better engineering properties in terms of stability, flow value, air voids and water absorption comparing with non-modified mixtures.