Microporous carbon catalysts with large surface areas (800-1100 m(2) g(-1)) and high densities of SO3H groups (ca. 1.1 mmol g(-1)) were synthesized by sulfonation of zeolite-templated microporous carbon. The resulting SO3H-bearing microporous carbon catalysts exhibited higher catalytic performance for the hydrolysis of cellobiose and the Beckmann rearrangement than conventional solid acid catalysts and non-porous amorphous carbon with SO3H groups. The high catalytic activity of these reusable heterogeneous catalysts can be attributed to the high surface area and microporous structure, which enhance the efficient incorporation and diffusion of reactant molecules from solution to the SO3H groups on the catalysts.