We quantitatively evaluated mitigation potentials of greenhouse gas emissions from agriculture and land use sectors in Indonesia. We also determined for the land use sector 1) how much time is needed to plan the mitigation strategy, and 2) how much time is needed to evaluate the effectiveness of mitigation measures? We used a bottom-up type model on emission mitigation named Agriculture Forestry and Other Land Use Bottom-up model (AFOLU-B model) to consider a characteristics time sequence of actions, effects and costs of mitigation countermeasures. To input to the model, we developed future scenarios on human activities in these sectors based on data from Indonesian government. We found that i) evaluation on effects and costs of mitigation measures from a long-term viewpoint and their continuing implementation are required to increase future mitigation potentials under a limited budget. ii) a long-term reduction target will also play an important role for cost-effective countermeasure selection. iii) reforestation of slow glowing species and enhanced natural regeneration will cause great increase in mitigation potential in the country.