Based on the two surveys of rice straw management in the Mekong Delta, Vietnam and Central Luzon, Philippines, a cost ? benefit analysis was conducted to assess whether rapid composting and straw mushroom production are options for Vietnam and Philippines to mitigate methane emission. The analysis showed that both the alternatives have potential to mitigate methane emission in Vietnam and Philippines. In the Mekong Delta, Vietnam shifting to straw mushroom production brings positive and higher NPV than shifting to rapid composting. The later only brings environmental gain in CH₄ reduction but not economic gain as indicated by their negative NPVs. In Central Luzon, Philippines, shifting from leaving the straw in the field to rapid composting and straw mushroom production gave high NPV and CH₄ reduction as the former would result in higher CH₄ emission. Shifting from burning to rapid composting result in negative NPV whereas shifting from burning to straw mushroom growing would yield positive NPV. Growing straw mushroom is a potential in augmenting farmers? income in both Mekong Delta and Central Luzon; however, requires them to invest more than other uses of rice straw.