This review is concerned with the preparation and electric properties of conductive carbon black/metal oxide gel nanocomposites prepared by sol-gel reaction of tetraethoxysilane (TEOS) or aluminium isopropoxide (AIP) in the presence of polymer-grafted carbon black. Polymer-grafted carbon black was  synthesized  by three methods (1) cationic polymerization of N-vinyl-2-pyrrolidone, (2) cationic ring-opening polymerization of 2-methyl-2-oxazoline (MeOZO), and (3) radical polymerization of vinyl monomers. The poly-condensation of TEOS and AIP proceeded under acidic condition in the presence of polymer-grafted carbon black to give deep black carbon black/silica gel and carbon black/alumina gel nanocomposites, respectively. Carbon black was uniformly incorporated  into silica gel and alumina  gel matrices  by hydrogen bonds between carbonyl groups of the grafted polymer and the residual by hydroxyl groups in the metal oxide gel. Scratch hardness of the polymer-grafted carbon black/metal oxide gel nanocomposites tends to decrease as the content of polymer-grafted carbon black increased. Electric  resistance of the polymer-grafted  carbon  black/alumina gel nanocomposite  was very sensitive to the  vapor of good solvents for the grafted polymer chains: the electric resistance of the nanocomposite  drastically decreased in humidity and N,N-dimethylformamide vapor, but not in n-hexane  vapor. The logarithm of electric resistance of poly(MeOZO)-grafted carbon black/alumina gel nanocomposite linearly decreased in proportion to relative humidity. In addition, the electric resistance of electric resistance of poly(N,N-diethylacrylamide)-grafted carbon black/alumina gel nanocomposite shows negative temperature coefficient: the electric resistance under humidity drastically decreased at 32º C.