The new copolymers based on maleic anhydride and .alpha.,.beta.-unsaturated compounds contain, as bivalent structural units,A: 20 to 95 mole % of the structural element ##STR1## B: 0 to 40 mole % of the structural element ##STR2## C: and 0 to 40 mole % of the structural element ##STR3## the sum of the mole percents of (A), (B) and (C) being 100, and wherein R.sup.1 and R.sup.2 are identical or different and denote hydrogen, alkyl, optionally substituted aryl or the ester group ##STR4## in which R.sup.4 represents alkyl with 1 to 20 carbon atoms,R.sup.3 denotes an alkyl, cycloalkyl or optionally substituted aryl radical with 1 to 20 carbon atoms andX and Y are identical or different and represent the group--O--R.sup.5in whichR.sup.5 denotes hydrogen, a cation or alkyl with 1 to 40 carbon atoms, orX and Y represent the group--NHR.sup.3in which R.sup.3 has the abovementioned meaning,at least one of the radicals X and Y representing the group --O--R.sup.5, and at least one of the radicals in the radicals X and Y containing at least 18 carbon atoms.The new copolymers can be prepared by reacting alternating copolymers of maleic anhydride and .alpha.,.beta.-unsaturated compounds with monoalcohols and monoamines. They can be used as paraffin inhibitors.