Concrete is a composite material consisting of Mortar and aggregate. The main problem in the concrete is the formation of cracks. In this study, to control the cracks into the concrete steel fibers are added. Now a day the use of PET (polyethylene terephthylate) is highly recommended. This thesis has studied the incorporation of polyethylene terephthalate (PET) waste in concrete as a substitute for natural coarse aggregate and has found an optimal combination of components that produces a useful concrete product. The waste PET was first reduced in coarse aggregate by shredding and then combined with the rest of the components. A traditional method will use for the partial replacement of polyethylene terephthalate (PET) as coarse aggregate to its weight with the addition of steel fiber, which is 1%, 1.5% and 2% by volume in plain concrete. Specimens of specified are used for testing, which is designed according to the Indian standard code. Compressive, tensile and flexural strength of this specimen compared to the control sample and then 5%, 10%, 15% and 20% of polyethylene terephthalate (PET) are partially replaced as coarse aggregate samples. Furthermore compressive, tensile and flexural strength of this new specimen compared to the control sample. The material used in this experiments are; Cement, fine aggregate, coarse aggregate, PET as a partial replacement of course aggregate and water. Therefore, the main objective of this study is to use PET as a partial replacement of course aggregate in concrete. The safety, durability, and stability of the structure depend to a large extent on the properties of the concrete and, therefore, it is imperative to prepare the concrete with adequate strength.