Livestock is one of the major sources of non-CO₂ greenhouse gas (GHG). Methane (CH₄) is emitted through enteric fermentation or both CH4 and nitrous oxide (N₂O) is emitted from manure management, thus they need to be mitigated to tackle the climate change issue. This report summarizes the research effort on mitigation of GHG emissions from livestock sector in SE Asian countries, including improvement of feed efficiency to reduce the emission intensity, utilization of several promising feed additives and others. For the manure management, GHG emission factor (EFs) database has been built for precise estimation by international cooperation framework and dataset from Japan also included. The database highlights the significant geographical unevenness of the available dataset. The EFs for SE Asian countries are extremely limited while majority of dataset comes from western countries, the effort for data generation in this region is also ongoing. Here we show the examples in Vietnam and Thailand for potential EFs measured under local conditions. In addition, we detected the significant manure flow into central highland in Vietnam, where active coffee/pepper intercropping system occurs. In this region, dried cattle manure is composted with coffee husk, so here we provide another example on GHG EFs from this specific composting system in Vietnam.