Riau is one of the provinces that has the most palm oil mill in Indonesia. The palm oil mill activities produce carbon dioxide emissions from it processes. This study aims to calculate carbon dioxide emissions from the palm oil mill and plan it mitigation efforts. This research was conducted at one of the palm oil processing plants in Kampar district, Riau Province. Palm oil mill utilizes biomass in the form of fibers and shells of palm fruit as boiler fuel to generate electricity, in addition from the use of generator sets. The palm oil mill produces liquid waste. In the process of transporting palm fruit from the garden to the factory, it also produces emissions from transportation. The results of this study showed that carbon dioxide emissions from palm oil mill amounted to 709,436.87 ton CO2 eq/year. The mitigation efforts that can be carried out are by catching methane gas produced from the process of treating liquid waste and turning it into electricity. The electricity generated would meet the energy needs of the plant so that it could eliminate the use of boilers and generator set, eventually the carbon dioxide emissions produced from palm oil mill can be reduced by 99.23%.