AbstractWhen sugarcane bagasse was pretreated at room temperature with various chemicals singly or in combination, (0.25 m NaOH; 0.5 m H2SO4; 2.6 M NH3;0.14 M Ca(OH)2+0.12 M Na2CO3;4.2 m EDA; and 0.5 M H2SO4or 0.25 M NaOH followed by 4.2 M EDA), increases in in‐vitro digestibility range from 28.9 to 48.6% depending on the particular chemicals. With most pretreatments, the hemicellulose content decreased and the cellulose content increased slightly, while lignin levels decreased only with NaOH + EDA pretreatments. Further fermentation of the chemically pretreated bagasse withPhanerochaete chrysosporiumgave increased digestibilities, the highest final digestibility (59%) being achieved by pre‐treatment with 0.25 M NaOH. Pretreatment with NaOH or Ca(OH)2+Na2CO3and fermentation gave greatly increased levels of hemi‐cellulose and cellulose and substantial decreases in lignin levels. Chemical pretreatments of bagasse together with autoclaving considerably enhanced in‐vitro digestibility (up to 75%) and lignin degradation (1.4%). Pretreatment with NaOH, Ca(OH)2+Na2CO3, and EDA plus autoclaving gave large increases in total hemicelluloses and cellulose and marked decreases in lignin. Further fermentation withP. chrysosporiumgave only slight increases in digest