Different pretreatments were evaluated on corn stalk (Zea mays) applied as a lignocellulosic source in anaerobic co-digestion with swine manure, using sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) for biogas production purposes. Using H2SO4 we achieved a 75.1% removal of the hemicellulose fraction, in low acid concentrations (0.75% v.v(-1)). However, this technique inhibited the co-digestion process. Pretreatment with 12% of H2O2 (pH 11.5) increased the cellulose fraction by 73.4% and reduced the lignin content by 71.6%. This pretreatment is recommended for biogas production, as it increased the final volume of biogas by 22% and reduced the digestion time by one third. So, a promising alternative was obtained in order to facilitate the anaerobic digestion of the carbohydrates present in this biomass.