Concrete is a man made material used in construction of buildings, industrial structures, highway and bridges etc. which is a mixture of cement, aggregates and water in required proportion. The addition of coconut-fibers significantly improved many of the engineering properties of the concrete, compression strength and tensile strength. Basically natural fibers are of two types. Natural inorganic fibers such as Basalt, Asbestos…etc and the other are the natural organic fibers such as coconut, palm, kenaf, jute sisal, banana, pine, sugarcane, bamboo..etc. When coconut fiber was added to plain concrete, the compressive strength and tensile strength increased (by up to about 25%) as well as the energy-absorbing capacity, but there is an optimum weight fraction (0.5% by weight of cement) beyond which the compressive strength and tensile strength started to decrease again.