The aim of this study was to characterize microfibrillated cellulose (MFC) produced with a Masuko Sangyo Super Masscolloider using bleached and unbleached pulp of Eucalyptus spp. The MFC was characterized regarding morphology (TEM), crystallinity, viscosity, zeta potential and thermal properties (TGA). Regardless of the fiber type, the processing dramatically reduced the dimensions of the material, so as to obtain structures with nanometric dimensions. MFC produced with unbleached pulp preserved the original brown color of the pulp, which may be advantageous for some applications in the packaging sector, while films produced with bleached pulp were more translucent. The MFC showed lower values of viscosity and crystallinity index in relation to cellulosic pulp. The zeta potential was influenced by the type of fiber used. The main thermal transitions in MFC occurred after 200 ºC, demonstrating the potential of this material forhigh-temperature applications.