It is known that water is the first enemy of asphalt pavement, and its danger increases when the water is a product of sewage because it contains organic materials and acids. The most common technique to mitigate moisture damage is using of additives or modifiers with the asphalt binder or the aggregate. The objective of this research is to study the effect of wastewater on the mechanical properties of HMA containing chemical additives. Three different chemical additives were used. The chemical additives were Addicrete PVS, Adibond 65 and Silica Gel that were added with different percentages 5, 10, 15 and 20 % by the weight of optimum asphalt content in additional to the original mix. All asphalt mixtures were submerged in wastewater for 3, 7 and 15 days. Marshall and Indirect tensile strength tests were performed on these exposed mixtures in spite of that the wastewater decreased the mechanical properties of all mixtures the additives decrease that effect with pronounced values. The best additive was Addicrete PVS with 10% content of (O.A.C) as it gives the highest value of Marshall stability, Marshall stiffness, Marshall quotient and indirect tensile strength.