The conversion of agricultural waste into valuable products is a critical endeavour in the pursuit of clean and sustainable environment. Biochar has recently emerged as an effective composite filler. However, the choice of biomass for biochar production is critical in determining its properties, which in turn influence the performance of composites. This study investigates the impact of using agricultural wastes cashew nutshell and sugarcane husk for biochar production. Cashew nutshell waste and sugarcane husk waste were pyrolyzed at 400 degrees C for 3 h and biochar was produced, which was used as a filler in polyester matrix. The mechanical and erosive resistance properties of the resultant polyester composites were evaluated. The results revealed that both biocharincorporated composites significantly improved the mechanical strength and erosion resistance. Notably, the sugarcane husk biochar composite has higher mechanical strength and erosion resistance. This highlights the value of sugarcane husk waste as a valuable resource for biochar production in composite materials, a significant step towards sustainable waste utilisation and the development of high-performance composites suitable for a wide range of applications.