The present invention is directed to the use of alkyl(meth)acrylate polymers or copolymers of the formula (I) In-Poly-(E)y  (I) as cold flow improvers in biodiesel fuel (or bio-fuel) and biodiesel compositions incorporating said polymers or copolymers, obtained by nitroxyl mediated controlled free radical polymerization, wherein In is the initiator fragment starting the polymerization reaction; E is an end group bearing at least one stable free nitroxyl radical, which is bound via an oxygen atom to the polymer or copolymer; or a group which results from a substitution or elimination reaction of the attached stable free nitroxyl radical; Poly is any polymer or copolymer formed from ethylenically unsaturated monomer(s); and y is a number 1 or greater than 1 indicating the average number of end groups E attached to Poly.