With the aim to explore the potential contributions of discarded coconut fibers (DCF) as reinforcement in concrete the hardened properties of coir concrete of similar slump, with different fiber lengths and dosages are analysed in this paper, including compressive strength and stiffness, flexural response, and mainly the resistance to impact loading using two tests, that proposed by the ACI Committee 544 and a new method based on the application of Growing Impact Loads. It was found that DCF yields similar effects as synthetic microfibers in fresh and hardened properties of concrete but the incorporation of longer DCF shows improvement in terms of impact resistance