For the first time, a series of carbon nanofiber (CNF)/polydimethylsiloxane(PDMS)-based nanocomposites was prepared using in situ polymerization technique by critical manipulation of factors, such as method of preparation and chemical modification of filler. Quantification of the degree of dispersion was done by introducing a dispersion degree parameter. Extent of dispersion was found to improve by amine modification of CNFs. Electrical conductivity was found to undergo profound increase when compared with that of the insulating base polymer. Amine-modified CNF-based nanocomposites showed percolation threshold at lower filler loading compared with unmodified CNF-based nanocomposites. These results of electrical properties measurements were correlated with the results of TEM analysis.