A wire or cable comprising a conductor or wire core and a coating layer on the exterior of the conductor or wire core which is formed from a rubber or plastic composition containing a rubber or plastic and an inorganic filler having high moisture resistance is provided. The inorganic filler is the one which has been surface treated with an alkoxy group-containing organopolysiloxane having an unsaturated aliphatic group-containing group and a monovalent hydrocarbon group of 3 to 10 carbon atoms containing no aliphatic unsaturated bond obtained by partially cohydrolytic condensation of an organic functional group-containing silane and/or its (partially) hydrolytic condensate, and an organic functional group-containing silane and/or its (partially) hydrolytic condensate.