Today Indonesia is contributing to more than half of the global palm oil production, with ap-proximately 34.5 million tons produced in 2016. This production has been projected to in-crease to 50 Million tons by 2025. To reach this level of production and still maintain its committed sustainability standards, Indonesia will have to address a triple challenge: protect-ing high conservation areas, such as primary forest and peatland; closing the yield gap be-tween smallholders and agro-industries; and reducing the environmental impact of existing oil palm plantations. In this context, we chose to focus on the third challenge and investigated the opportunity of composting palm oil mill by-products to mitigate the environmental impact of palm oil production. We studied the composting process in palm oil plantations and analyzed the results from waste management, agronomic and environmental perspectives. We conducted experimental co-composting of empty fruit bunches (EFB) and pre-digested palm oil mill effluents (POME). We studied the effect of the ratio of POME to EFB and the turning frequency of the compost using a split-plot experimental design comprising 24 com-post heaps, in a covered composting platform on a concrete floor. The composting process lasted 60 days, during which the compost piles were regularly turned and sprayed with POME. We found that the biological degradation composting process reduced the dry weight of EFB by 45%. It also led to the evaporation of 60% of the water contained in POME and the EFB, thereby considerably reducing the amount of waste that comes out of the palm oil mill. In terms of recycling efficiency, a recovery rate close to 100% was achieved for K, P and Mg. We also observed loss of Nitrogen of about 25-30% during the composting process. We found that a high POME to EFB ratio (3m3/ton EFB) increased moisture above optimal water content and reduced free air space within the compost piles. Adding too much POME to the EFB also increased