In this study nanobiocomposites composed of two biodegradable polyesters, poly (butylene succinate - co - adipate) (PBSA) and polycaprolactone (PCL) with cellulose nanocrystals grafted PCL (CNC - g - PCL) were prepared through melt extrusion. The studied compositions were blends of 30/70 and 50/50 PCL/PBSA (wt.%) with 0, 1, 3 and 5 wt.% CNC - g - PCL. The CNC were prepared by sulfuric acid hydrolysis from eucalyptus wood pulp. Transmission electron microscopy (TEM) showed that the CNC have an average length of 145 ± 25 nm and average width of 6,0 ± 1,5 nm. A grafting from approach was used to graft PCL to CNC by Sn(Oct)2-catalyzed ring-opening polymerization. Results of infrared spectroscopy (FTIR) confirmed the grafting of CNC with PCL chains. Wide angle x-ray diffraction (WAXD) results showed that the grafting did not alter the crystallinity or morphology of the CNC. Thermogravimetric analysis (TGA) showed that the grafting increased the thermal stability of CNC, however a decrease of the thermal resistance of the nanocomposite with increasing content of CNC - g - PCL was observed. The immiscibility of the polymer was confirmed through differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The stiffness of the material was confirmed from the tensile test, where the elastic modulus approximately twice increase with increasing CNC - g - PCL content in the nanocomposites, on the other hand the elongation at break decreases. These properties clearly demonstrate the potential applications for CNC - g - PCL in the field of nanobiomaterials.