Renewable natural-based composite materials, including wood fibers and plants, represent emerging research interests that continue to be developed today. Among the 120 types of Indonesian wood traded, Sengon, Keruing, and Yellow Meranti are most widely used in the wood industry. The processing of wood produces end waste products, for example sawdust, which have the potential to be used as reinforcements or fillers in Polymer Wood Composite materials. In this study, composites were made using unsaturated polyester matrices and sawdust. The sawdust was alkalinized with a 5% Sodium Hydroxide (NaOH) solution and confirmed with Fourier-Transform Infrared (FTIR). Tests on mechanical properties included tensile and bending tests, followed by Scanning Electron Microscopy (SEM) to observe the fracture surface of the tensile test results. The composites produced from the three types of wood exhibited a significant increase in mechanical properties compared to pure wood.