Composites used as particleboard have recently been developed using waste-paper fibers mixed with natural rubber compound at a weight ratio of 70/30 %. The effects of silica and aluminum hydroxide fillers were studied at 0, 15, 30, 45, and 60 phr. The results showed that the hardness of the waste-paper particleboard increased with the filler content. Both types of fillers led to a slight increase in the density of the composites. Moreover, the fillers reduced the hygroscopicity and swelling of the particleboard. The use of silica resulted in lower hygroscopicity, providing greater flexural resistance and elastic modulus compared to using aluminum hydroxide. Additionally, the minimum limiting oxygen index (LOI) required to ignite the sample was slightly higher with the addition of both fillers, with silica exhibiting a higher value than filled aluminum hydroxide. Furthermore, the thermal decomposition of the specimens from the TGA test was reduced as both fillers were added, especially at temperatures above 350°C.