Process for the manufacturing of graft polymers of polysaccharides or polypeptides or its respective derivatives, obtainable by free radical induced co-polymerization of A) a monomer selected from or a monomer mixture of (a) from 20 to 100% by weight of acrylic acid or methacrylic acid or of a mixture thereof or of the alkali metal, alkaline earth metal or ammonium salts thereof, (b) from 0 to 80% by weight of other monoethylenically unsaturated monomers which are co-polymerizable with the monomers (a) and (c) from 0 to 5% by weight of monomers having at least 2 ethylenically unsaturated, nonconjugated double bonds in the molecule, in the presence of either B1) polysaccharides, oxidatively, hydrolytically or enzymatically degraded polysaccharides, oxidized hydrolytically degraded or oxidized enzymatically degraded polysaccharides, or such chemically modified degraded products, chemically modified mono-, oligo- or polysaccharides or mixtures of the stated compounds or B2) polypeptides, hydrolytically or enzymatically degraded and optionally chemically modified polypeptides or mixtures of the stated compounds in a weight ratio A:(B1 or B2) of from 1:99 to 18:82, wherein the components of the monomers of A) are added to B1) or B2) in an inert solvent at a temperature of 40 to 150 °C in the presence of a free radical-forming initiator, characterized in that at least 50% of the radical-forming initiator are with the component B1) or B2) before the addition of the monomers A) and the rest is added together with the monomers of A) and wherein the free radical-forming initiator is used from 0.05 to 15, % by weight, based on the monomers A used in the polymerization. A) a monomer selected from or a monomer mixture of (a) from 20 to 100% by weight of acrylic acid or methacrylic acid or of a mixture thereof or of the alkali metal, alkaline earth metal or ammonium salts thereof, (b) from 0 to 80% by weight of other monoethylenically unsaturated monomers which are co-polymerizable with the monomers (a) and (c) from 0 to 5% by weight of monomers having at least 2 ethylenically unsaturated, nonconjugated double bonds in the molecule, (a) from 20 to 100% by weight of acrylic acid or methacrylic acid or of a mixture thereof or of the alkali metal, alkaline earth metal or ammonium salts thereof, (b) from 0 to 80% by weight of other monoethylenically unsaturated monomers which are co-polymerizable with the monomers (a) and (c) from 0 to 5% by weight of monomers having at least 2 ethylenically unsaturated, nonconjugated double bonds in the molecule, B1) polysaccharides, oxidatively, hydrolytically or enzymatically degraded polysaccharides, oxidized hydrolytically degraded or oxidized enzymatically degraded polysaccharides, or such chemically modified degraded products, chemically modified mono-, oligo- or polysaccharides or mixtures of the stated compounds or B2) polypeptides, hydrolytically or enzymatically degraded and optionally chemically modified polypeptides or mixtures of the stated compounds in a weight ratio A:(B1 or B2) of from 1:99 to 18:82, wherein the components of the monomers of A) are added to B1) or B2) in an inert solvent at a temperature of 40 to 150 °C in the presence of a free radical-forming initiator, characterized in that at least 50% of the radical-forming initiator are with the component B1) or B2) before the addition of the monomers A) and the rest is added together with the monomers of A) and wherein the free radical-forming initiator is used from 0.05 to 15, % by weight, based on the monomers A used in the polymerization.