Abstract: Background and Objective: Utilization of soybean plants as cover crops under oil palm trees is one of the solutions to maintain food security in Indonesia. Therefore, the objective of this research was to study the effect of organic matter derived from the Oil Palm Empty Fruit Bunches (OPEFB) and Trichoderma harzianum + Pleurotus ostreatus (Tri-Po) combination to the leaf physiological properties and productivity of soybean planted under 4 years old oil palm stands. Materials and Methods: A factorial design with Randomized Complete Block Design was employed as environmental design. The first factor was OPEFB compost consisting of three levels and the second factor is the Tri-Po combination which consists of four levels. The treatments were repeated three times resulted in 36 experimental units. Observations focused on some physiological characteristics and agronomical characters of the soybean. Results: The results showed that the use of OPEFB compost applied with Trichoderma harzianum and Pleurotus ostreatus improved the biological, physical and chemical characteristics of the soil, enhanced the physiological performance and productivity of soybean plants. The combination of 10 kg ha–1 OPEFB and 4g:6g Tri-Po was the best formula to improve the physiological characters of soybean leaves grown under oil palm stands. Conclusion: The research can increase the land economic value of smallholder or palm oil industry and increased the soybean supply for domestic demand.