The global energy scenario brings to light the need for the search for renewable sources that contribute positively to the reduction of harmful gases emission, such as CO2. In this context, studies such as the one herein constitute an important contribution to a better understanding of these environmental issues. The purpose of this study was to evaluate the effect of the alkaline pre-treatment (mercerization, NaOH 20%, 20 g.L-1, room temperature, 5h) on saccharification, via acid and enzymatic hydrolysis of curauá lignocellulosic fibers (moisture content 8.2% ± 0.2, ashes 2.0% ± 0.1, holocellulose 85.9% ±0.7, hemicellulose 15.5% ±0.2, α-cellulose 70.4% ± 0.2, total lignin 9.4% ± 0.3 and crystallinity index, (Ic, 69.4%). Aliquots removed during mercerization were characterized. For example, the aliquot referring to 2h had the following properties: α-cellulose 81.6% (± 0.2), total lignin 3.2% (± 0.3) and crystallinity index (Ic) 75.5%. Analyses of scanning electron microscopy (SEM), length and average thickness (MorFi) showed increased roughness and fragments adhered to the fiber surface and a decrease in length and thickness throughout the mercerization. Untreated and treated fibers (2h) were subjected to acid hydrolysis (1:30 vol./M.H2SO4 24%, 80°C, 6h), in which the unreacted fibers were separated from the liquor via filtration, and then characterized by X-ray diffraction, MEV, MorFi; liquor sugars and decomposition products were analyzed via High Performance Liquid Chromatography (HPLC). The results of the acid hydrolysis with the mercerized fiber presented higher glucose production (cellulose fraction) and decreased xylose and arabinose contents (hemicellulosic fraction). The maximum glucose content obtained was 2.68 g.L-1, while for the hydrolysis with the untreated fiber the maximum was 1.3 g.L-1, in which there was low-scale formation of decomposition products (HMF and furfural). No mercerized and mercerized fibers were also subjected to enzymatic hydrolysis (48h, commercial cellulase enzymes-Accellerase 1500, 0.5mL / g). Aliquots of the unreacted pulps and liquor were extracted during the reaction, and then characterized as described for acid hydrolysis. Microscopies showed that there was an increase in roughness and in the opening of fiber bundles in the mercerized fibers. The crystallinity indexes showed an initial increase and a subsequent decrease indicating hydrolysis of the non-crystalline fraction of the cellulose followed by the crystalline fraction. The length and average thickness of the fibers decreased, which was more accentuated in the hydrolysis with the mercerized fiber and more intense as for the thickness. There was formation of glucose and xylose and there was no formation of decomposition products as occurred in acid hydrolysis. For the untreated fiber, a maximum glucose of 12.0 gL-1 and 2.30 gL-1 of xylose was obtained, whereas the mercerized fiber presented a maximum of 17.5 gL-1, 1.36 gL-1 of glucose and xylose respectively, indicating a 45% increase in glucose and a 56% decrease in xylose. This investigation of the effect of mercerization on the saccharification of the curauá fiber provided important information for further studies, as well as indicating that the curauá can later become a source of second generation ethanol production. Keywords: Curauá Fiber. Mercerization. Acid and Enzymatic Hydrolysis. Glucose.