This paper reviews current research, techniques for characterization and trends on the field of nanocomposites. Nanocomposites are new materials made with fillers which have nanosize. These materials have a big potential for applications in the automotive and aerospace industry as well as in construction, electrical applications and food packing. There is a tremendous interest for using bio-nanoparticles like cellulose microfibrils or whiskers to be applied in the new era of biocomposites