Carboxylated Nitrile Butadiene Rubber (XNBR) was reinforced with untreated and silane treated hybrid filler. The hybrid filler was composed of organic layered nanosilicates (NLS) and agro polymer based olive husk powder (OHP). The fabricated composites were inspected with regard to their mechanical and thermal properties. It was found that the silane treated hybrid filler was able to improve the tensile strength at break and the tensile modulus as compared to the control. The overall degree of interaction between the matrix and both the untreated and treated hybrid filler was improved. This was evidenced by the increased degree of curing which is the torque difference (tau(max)-tau(min)) derived from the moving die rheometer (MDR) and the decreased swelling index data. Dynamic mechanical analysis (DMA) revealed that the apparent was the highest in case of the silane treated hybrid filler. The thermogravimetric analysis (TGA) revealed that the thermal stability of the composites improved with the incorporation of the hybrid filler. The attenuated total reflectance (ATR-IR) revealed that dipole-dipole interactions between the various reactive functional groups namely the carboxylic of the XNBR, the hydroxyl group of the agro-polymer and the silanol of the silane agent occurred during the fabrication stage of the composites. Scanning electron microscopy (SEM) showed that the fracture surface of the samples differ after the incorporation of the treated hybrid filler.