Added-value bionanocomposite films were obtained using exclusively oceanic biomass, i.e. chitin nanofillers (nanocrystals- CHNC and nanofibers- CHNF) and chitosan (CS) isolated from Cervimunida johni (yellow lobster) wastes. From these raw materials two sets of bionanocomposite films (CSICHNC and CS/CHNF) using CS as matrix and CHNC or CHNF as functional agents were prepared by solvent evaporation-casting approach. The bionanocomposite films' chemistry, structure, mechanical and thermal properties and fungal growth inhibition toward A. niger were analyzed, and the effect of the CHNC and CHNF on the final properties of CS-based bionanocomposite films was evaluated and compared. The data demonstrated that the final properties were dependent of the content and nano nature (size and shape) of chitin nanofillers incorporated in the CS matrix. The CS-based bionanocomposite films reinforced with CHNF showed superior mechanical properties than those prepared with CHNC. Moreover, antifungal assessment demonstrated that CS/CHNF bionanocomposite films presented an inhibitory effect (FGI >80%) against A. Niger. Unquestionably, these bionanocomposite films show a great potential to be used in packaging applications and medical devices. (C) 2015 Elsevier B.V. All rights reserved.