Peanut shell was selected as a representative agricultural by-product and a catalytic process was applied to convert it into oxygenated organic compounds. Bases, acids, and supported metal catalysts were used in a batch reactor at various reaction conditions and organic solvents or solvent mixtures. Products and their distribution were analyzed by GC/MS. In general, base catalysts showed higher conversion rate in terms of total carbon and more favorable to the generation of wide range of lower molecular weight organic compounds. Using supercritical methanol as solvent achieved a ~60% conversion of biomass and produced predominantly methoxyl phenolic compounds. Effects of supported metal catalysts varied depending on metals and supporting materials.