A fuel oil containing a conductivity improving additive comprising the combination of: (a) a polymethacrylate, polyacrylate or polyfumarate polymer not prepared from a quaternary ammonium monomer and having a number average molecular weight of about 1,000 to 10,000,000 and either (b) a conductivity improver comprising (i) an olefin polysulfone and (ii) a polymeric polyamine reaction product of epichlorohydrin and an aliphatic primary monoamine or an N-aliphatic hydrocarbyl alkylene diamine, or the sulfonic acid salt of the polymeric polyamine reaction product or (c) a conductivity improver comprising a hydrocarbon soluble copolymer of an alkylvinyl monomer and a cationic vinyl monomer, wherein the copolymer has an alkylvinyl monomer unit to cationic vinyl monomer unit ratio of from about 1:1 to about 10:1, the copolymer having a number average molecular weight of from about 800 to about 1,000,000.