Bionanowhiskers were extracted from jute by acid hydrolysis. At first cellulose microfibrils were formed by alkali treatment. Addition of an acid to the microfibrils triggered the formation of cellulose nanowhiskers. These were characterized by using different techniques viz. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). In the FTIR study, absence of peak at 1738 cm(-1) indicated removal of hemicellulose. The rod like morphology of the nanowhiskers (length - 550±100 nm, width - 77±30 nm) was observed after 1h of acid hydrolysis, whereas further increase in time resulted in triangular shape morphology. Acid hydrolysis increased crystallinity, but decreased the temperature corresponding to major degradation (T(max)) and onset of degradation (T(i)). These bionanowhiskers might be useful as reinforcing element in nanocomposites.