Palm fronds and mango's dry leaves are examples of the agricultural wastes (AW), which are added as reinforcement materials for the polyester, as one of the polymer composites. This work is to investigate the effectiveness of these reinforcements in improving the tribological properties of the polyester composite. Two factors have been taken into consideration when designing the experiment. First is the size of the added particles; soft and hard particles with 0.5 mm and 3 mm particle size respectively were used. Second factor is the percent of the weight of the added waste (WOAW %) to the weight of the whole test specimen, ranging from 0% to 50%. A Pin-on-disc tribometer has been used to perform the tribological measurements. Polynomial regression analyses have been made. Trends and Coefficients of correlation have been obtained and used as the assessment measures. The results show that agricultural wastes improve the tribological properties of polyester composite.