A middle and/or heavy distillate composition having a good flow property and filterability, comprising a fuel oil of varying proportions of middle and/or heavy distillate of petroleum and 10-2000 ppm, based on the fuel oil, of a mixture of 1-99% by weight of (A) a copolymer of ethylene with an alkoxyalkyl acrylate or methacrylate represented by the formula, ##STR1## wherein R.sub.1 represents hydrogen or C.sub.1 -C.sub.2 alkyl and R.sub.2 is C.sub.m H.sub.2m --O--C.sub.n H.sub.2n+1, m and n each being an integer of 1-4, and 99-1% by weight of (B) a copolymer of ethylene with a vinyl ester of saturated carboxylic acid and/or an alkyl ester of ethylenic unsaturated carboxylic acid.