The invention relates to additives for improving lubricating properties of fuel oils, comprising A) 10-95% by weight of at least one oil-soluble amphiphile which comprises nitrogen- or oxygen-containing groups substituted by alkyl, alkenyl, hydroxyalkyl or aromatic radicals, and B) 5-90% by weight of at least one copolymer which contains B1) from 0.5 to 15 mol % of structural units which are derived from olefinically unsaturated compounds which have at least one free hydroxyl group, and B2) from 85 to 99.5 mol % of structural units which are derived from ethylene, and, if required, B3) from 0 to 20 mol % of further structural units selected from the group consisting of (meth)acrylic acid, (meth)acrylates, vinyl esters, vinyl ethers and alkenes, and the copolymer has an average molar mass Mw of from 500 to 100,000 g/mol and an OH number of from 5 to 500 mg KOH/g.