Elastomer blends are used in many applications in industry. Combination of natural rubber (NR) and butadiene rubber (BR) is widely used in suspension elements, tread, and sidewall parts of tire. NR/BR blends are immiscible as reported previously. Compatibilization of immiscible blends by using nano-scale particles is a common practice. Layered silicates, carbon nanotubes (CNTs), fullerenes, silica, and metallic nanoparticles, metal oxides are used in rubber composites to enhance matrix-filler interaction. Alternative to conventional nanofillers, polyhedral oligomeric silsesquioxanes (POSS) nanoparticles are useful candidates to compatibilize the immiscible polymer blends due to its hybrid structure. Inorganic structure of POSS can create a molecular reinforcement for polymers and the organic groups on the POSS unit that can improve the compatibility between the polymer blends. In this study, POSS having different functional groups incorporated NR/BR blends were prepared by using laboratory scale internal mixer. Vulcanization was performed by using hydraulic hot press at 160˚C. Mechanical properties were determined by tensile and compression tests. Dynamic mechanical properties were investigated in tension mode by using dynamic mechanical analyzer (DMA). The morphology of NR/BR vulcaniztates was also studied by scanning electron microscopy (SEM).