Pre-extractcd rice stalks were decayed with the white-rot fungus Phanerochaete chrysosporium. Results showed that rice straw lignin degraded more rapidly than that in spruce and birch. Nitrobenzene oxidation data indicated that rice straw lignin contained higher proportion of condensed aromatic units. The fungus first attacked noncondensed aromatic units, but syringyl propane units were not decayed substantially faster than guaiacyl units. Analytical data also showed that demethylation occured during the decay.