The cost of cement, which is used in concrete works, is rising and becoming unaffordable, but as the population grows, so does the need for homes and other structures that require this material. Because Portland cement is produced using a lot of CO2, it has a major environmental impact. Because it helps to reduce the use of natural raw materials as resources, the use of secondary materials or industrial waste in the production of cement and concrete has been promoted in the building industry. The world's waste output has grown over time as a result of socioeconomic progress, population growth, and socioeconomic activity. Looking at the prospect of waste minimization and reuse is one of the most appealing ways to manage such waste. In this instance, agricultural waste material, coconut shells, which are environmentally polluting, are gathered and burned without oxygen (pyrolysis). The resulting ash from the burning process is then used as pozzolana, partially replacing 0%, 5%, 10%, 15%, and 20% of ordinary Portland cement with ash from coconut shells. Concrete grade M20 having a mix ratio of 1:1.5:3 was used in the course of this project and a water cement ratio of 0.55 was maintained. This experiment indicates that the addition of Coconut Shell Ash (CSA)into cement composite does increase the compressive strength but the strength only increases up to certain CSA content. Specimen with 10% CSA gave the highest compressive strength of 28.3 N/mm² and this optimum strength dropped when the CSA content is further increased from 10%-20%. At 7 and 14days, the experiment shows a low compressive strength of specimens compare to the result at 28 days which gave the highest compressive strength.