In recent years, several studies have been performed using nanocellulose as a component in polymeric nanocomposites. The interest in studying cellulose-based nanocomposite is due to the abundance, renewable nature, and outstanding mechanical properties of this nanoparticle. However, obtaining nanocomposites based on nanocellulose, with optimal properties, requires good nanoparticle dispersion in the polymeric matrix. The chemical compatibility between nanofiller and polymer plays a major role in both the dispersion of particles in the matrix and the adhesion between these phases. The aim of this review is to present the fundamental concepts about nanocellulose, such as its structural aspects, production methods and current trends in classification, and the main aspects about cellulose-based nanocomposites, including the progress that has been reached in relation to their compatibilization, production, final properties and potential applications. F. A. dos Santos et al. 258 properties such as biodegradability, biocompatibility, low toxicity, and low cost among others [4]. These properties provide a great potential for use in applications from plastic bags and packaging to biomedical fields, including bone plates, fixation screws or sutures. However, to replace petroleum-based thermoplastics, biopolymers need to have comparable properties and processing methods to those conventionally used. In order to improve their properties, many biopolymers have been used in the preparation of nanocomposites [1].Similar to conventional composites, nanocomposites are composed of at least two components; one of them is the matrix or continuous phase, in which nanosized particles are dispersed. These nanosized particles or nanoparticles constitute the second phase, referred to as the dispersed phase. Polymer nanocomposites are a recent alternative to conventionally filled polymers. Due to the reduced size of dispersed phase and its good dispersion in the polymer matrix, these materials exhibit markedly improved properties when compared to the pure polymers or their traditional composites [5]. They also exhibit unique optical, electrical, and magnetic properties [6].Biopolymers, such as chitin, starch, and cellulose, can be employed as reinforcement filler or as matrix in the production of nanocomposites [2]. Cellulose is one of the best natural materials to generate nanofillers for producing nanocomposites that are based on renewable raw material sources, because it is the most abundant biopolymer in nature and is available in a wide variety of resources, such as plants and microorganisms [7]- [11].The nanofillers isolated from cellulose have been used as a reinforcing material in many natural and synthetic polymers [12]- [18]. The use of these nanofillers has proven effective due to the large surface area and the excellent mechanical properties presented by cellulose [19]. Furthermore, the addition of cellulose-based nanofillers promotes a better performance of the nanocomposite in relation to their barrier, thermal and mech...