Researches with sustainability subject have been intensifying in the recent years, making that materials from renewable sources receive special attention. Poly(lactic acid) is a biodegradable thermoplastic widely used in the manufacture of different products, from packaging to medical implants. Cellulose, a natural fiber, has excellent mechanical properties, achieved by the mechanical refining used in Pulp & Paper industry. Natural rubber is one of the most important rubber in our society, showing interesting properties such as tensile and fatigue strengths. This study aims at preparing and characterizing Poly(lactic acid)/refined-cellulose/Natural rubber composites. Pulps of cellulose was refined to produce three grades of refining, classified by Schopper Riegler test. Further, after mechanical refining, natural rubber latex was added to the pulp to produce a cellulose coated with natural rubber. Finally, different composites of Poly(lactic acid)/refined-cellulose/Natural rubber were prepared in twin-screw extruder. The fibers were characterized by scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and specific area Brunauer-Emmett-Teller. The composites were characterized by the morphology, thermal and mechanical properties.