Composites are comprised of combinations of two or more materials with different composition and macroscopically mixed while still having clear and identified boundaries. Natural fiber reinforced composites have replaced synthetic fiber reinforced composites because they have benefits including low density, low cost, recyclability, and corrosion resistance. Besides, fibers can be used to improve and rigidity of matrix powder. This study aims to investigate the effect of microparticles addition on the mechanical properties of kenaf/epoxy fiber composites. Kenaf fiber reinforced epoxy composites with ratio 30/70 (volume fraction) were fabricated using cold press method. The filler consisted of kenaf fiber ratio (± 6 mm length) with various amount of microparticle filler (20/10)% CaCO3, duck eggshell powder, and coating waste powder (400 mesh sieve). Charpy impact testing according to ASTM D 6110-04 and hardness testing ASTM E 10 has been adopted and implemented. In addition, the characterization of the structure area resulted from the impact test and microstructure of the cross-section fracture area were carried out using a scanning electron microscope (SEM, HITACHI SU3500) and optical microscope (OM, Olympus SZ61TR). The results showed that kenaf/epoxy fiber composites with the addition of CaCO3 powder microparticles had the highest impact toughness and Brinnel hardness at 513x10-3 J/mm2 and 52.57 BHN, respectively lowest value of impact toughness and Brinnel hardness are 363x10-3 J/mm2 and 19.09 BHN for the addition of powder coating waste microparticles. In addition, the results of microstructure characterization show that the distribution of filler in the matrix is relatively be spread evenly. The SEM results showed that debonding and voids still occur due to unfavorable suppression during the fabrication process, this causes the value of the composite mechanical strength to decrease.