Novelty of presented research is focused on ablation and thermomechanical characteristics of various loadings of carbon nanofibers (CNFs) of polyisoprene elastomer (PR). Conventional method (banbury disperser with open mixing mill) is applied to complete fabrication process of CNF-reinforced elastomeric nanocomposites. Scanning electron micrographs confirm the proper distribution of CNFs within the elastomeric host matrix. The successful incorporation of CNFs into PR has reduced the back-face temperature and increased the ablation resistance CNF/PR elastomeric nanocomposite in front of ultrahigh temperature (oxyacetylene flame exposure). Carbon nanofiber network with the elastomeric chain restricts the thermal transport within the CNF/PR nanocomposite specimens. The synergistic effect of CNFs on crystallization, glass transition, melting temperatures (Tm) of PR elastomeric nanocomposites is studied. Mechanical properties of PR are effectively enhanced by the impregnation of CNFs in the elastomeric nanocomposites.