This study focuses on the comparison of the mechanical properties of charcoal unsaturated polyester matrix composite and snail shell unsaturated polyester matrix composite. The ground charcoal powder and snail shell powder were of the same particle size of 625microns. The ground charcoal was introduced into the unsaturated polyester at different concentrations. The same concentrations of ground snail shell were incorporated into the same percentage of unsaturated polyester. The mechanical properties of the two resulting composites were compared. The mechanical properties tested include, ultimate tensile strength, tensile strain at maximum load, bending strength at peak, deformation at peak, hardness and impact strength. Significant findings showed that the flexural strength snail shell unsaturated polyester matrix composite at 20wt% reinforcement was better than that of the charcoal at the same concentration. Also, snail shell unsaturated polyester composite showed better hardness and impact strength than its charcoal counterparts and those of unreinforced unsaturated polyester. Therefore, where flexural strength, hardness and impact strength are of paramount importance such as in some automobile parts, snail shell reinforced unsaturated polyester composite should be given priority.