A semiconducting resin composition comprises: (A) 100 to 40 parts of a modified ethylene-vinyl acetate copolymer prepared by graft processing of 100 parts of an ethylene-vinyl acetate copolymer of a vinyl acetate content of less than 35 percent with 25 to 200 parts of an aromatic vinyl monomer; (B) 0 to 60 parts of a rubber; and (C) 3 to 150 parts of a carbon black with respect to 100 parts of the above described components (A) and (B), all quantities in "parts" and "percent" being by weight. A composition of this character has excellent characteristics for its use in forming the outer semiconducting layer of polyethylene-insulated cables.