Electrical, mechanical, and thermal properties of the poly(methyl methacrylate) (PMMA) composites containing functionalized multiwalled carbon nanotubes (f-MWCNTs) and reduced graphene oxide (rGO) hybrid nanofillers have been investigated. The observed electrical percolation threshold of FHC is 0.8 wt% with maximum conductivity of 1.21 x 10(-3) S/cm at 4 wt% of f-MWCNTs. The electrical transport mechanism and magneto resistance studied of hybrid composites have also been investigated. Progressive addition of f-MWCNTs in rGO/PMMA composite results increase in mechanical (tensile strength and Young's modulus) and thermal (thermal stability) properties of f-MWCNTs-rGO/PMMA hybrid nanocomposites (FHC). The increased mechanical properties are due to the efficient load transfer from PMMA matrix to f-MWCNTs and rGO through better chemical interaction. The strong interaction between PMMA and f-MWCNTs-rGO in FHC is the main cause for improved thermal stability. POLYM. ENG. SCI., 59:1075-1083, 2019. (c) 2019 Society of Plastics Engineers