This study aims to investigate the production of hydroxymethylfurfural (HMF) and furfural from cassava waste using a sulfonated carbon-based catalyst and to determine the suitable conditions for the reaction. With the use of the catalyst, the appropriate reaction medium for the production of HMF and furfural was a mixture of acetone/DMSO (70/30% w/w) and water at a ratio of 10/90% w/w. The reaction temperature and time were 250◦C and 1 min, respectively, and the corresponding weight ratio of the catalyst to cassava waste was 0.05:1. Furthermore, the carbon-based catalyst was found to be highly stable and thus can potentially replace the conventional homogeneous acid catalysts such as sulfuric acid for biomass conversion to liquid alkane. Particularly, the catalyst plays an important role in enhancing hydrolysis of cellulose and hemicelluloses and promoting the dehydration of xylose and glucose to form HMF and furfural.