The study deals with development of a new composite material with an objective to increase the mechanical and thermal properties. The proposed work involves the preparation of novel polymer based composite material reinforced with cenosphere and multi walled carbon nanotubes (MWCNTs) and to investigate fracture toughness and dynamic mechanical properties. MWCNTs have high tensile strength which contributes to increase in strength of composite as well as the load transfer capability. The 20 weight % of cenosphere and upto 0.5wt% of MWCNTs are used for the study. Dynamic mechanical analysis and fracture toughness tests of the composite were carried out. It was found that fracture toughness of the sample with 0.2 wt% MWCNT increased by 12% than the epoxy cenosphere composite. The results obtained by experimental test are compared with the simulation results. Thermal properties obtained by DMA have shown better thermal stability. The SEM analysis was carried out to study the interfacial bonding between the fiber-matrix and also to substantiate the fracture toughness result.