A new class of polyurethane (PU) biocomposites reinforced with green biocellulose nanofibers (BC) were designed and synthesized. These newly introduced non-cytotoxic and biodegradable composites were synthesized with different ratios of hard to soft segments of the linear, aliphatic hexamethylene diisocyanate (HDI) and polycaprolactone diol (PCL), respectively. The porosity was introduced in the polyurethane matrix using a combination of salt leaching and thermally induced phase separation (TIPS). BC contents were in the range of 0-15% of the final PU by weight. FTIR spectra showed complete conversion of HDI through the disappearance of the isocyanate and imine characteristic bands (at 2260cm(-1) and 1635cm(-1), respectively) and appearance of carbonyl group band in PU (at 1730cm(-1)). The hard to soft segment (i.e., HDI:PCL) ratios in the final PU polymer were quantified from H-1 Nuclear Magnetic Resonance (NMR) spectra by comparing the proton peaks arising for CH2CO at 2.25ppm or OCH2 at 3.9ppm to CH2N at 2.9ppm. Results showed that the ratios in the final product were consistent with the amounts added initially during the synthesis. Scanning electron microscope (SEM) images showed that porosity (57-75%) were formed (pore size in the range of 125-355 mu m), with an increase in pore content with the decrease in HDI:PCL content.