The compressive strength of concrete may be affected by the infiltration of saltwater. Dead Sea water is hazardous for concrete for the high concentration of salts. This study aimed to investigate the effect of water-repellent admixture on the compressive strength of concrete in highly aggressive ambient such as Dead Seawater and to determine the optimum percentage of admixture to be used. The study adopted an experimental approach in which the samples were divided based on the type of cement and the sample's age. Three types of cement were used (Ordinary Portland Cement, Pozzolana Portland Cement, and Sulphte Resistant Cement) with various percentages of water repellent admixtures (0%, 2%, and 4% of cement weight). Nine control samples were cured in natural water to ensure that the required compressive strength was reached and (54) samples were cured in Dead Seawater. The samples were tested at 7 and 28 days. From the results, it can be seen that a reduction in the 28-day compressive strength occurred in all specimens for the three types of cement used, but with the addition of water repellent, this reduction was alleviated, and the optimum percentage of admixture was 2% of cement weight. Key words: compressive strength, aggressive ambient, water repellent admixture, Dead Sea water.