Environmentally friendly nanocomposites comprising of cellulose and montmorillonite (MMT) were prepared via a green solvent, ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl) using solution casting method. The cellulose concentration and MMT content were varied according to predetermine formulation. The regenerated cellulose nanocomposites were characterized using X-ray diffraction (XRD). The thermal and thermal oxidative properties of regenerated cellulose nanocomposites were studied by thermogravimetric analysis (TGA). Mechanical properties of the nanocomposites films were investigated by tensile strength measurements. The intercalation and exfoliation of MMT in the cellulose matrix were confirmed by XRD results. TGA results showed an increment in degradation temperature and char yield for the nanocomposites. Multistep TGA graph was observed for degradation under air. The results indicated that the addition of MMT up to 6 wt% in regenerated cellulose matrix improved the tensile properties.