Novel, cationic graft copolymers with charged polyoxyethylene (PEO) side chains were prepared from the alternating copolymer poly(phthalimidoacrylate-co-styrene). Substitution of the good leaving phthalimido ester groups with alpha-trimethylammonioethyl-omega-aminopolyoxyethylene resulted in graft copolymers with PEO side chains end-functionalized with quaternary ammonium groups. In a two-step synthetic procedure the same precursor polymer was modified with 3-dimethylaminopropylamine. Then the tertiary amine groups were quaternized with alpha-methoxy-omega-bromopolyoxyethylene or with alpha-trimethylammonioethyl-omega-bromopolyoxye to yield graft copolymers with cationic groups close to the backbone or bearing bifunctional side chains. The effect of ionic group location on the behaviour of the copolymers in a low-polarity and a polar solvent was studied by viscosity, GPC and static light scattering measurements. In a low-polarity solvent (tetrahydrofuran) the factors determining the solution properties of the cationic graft copolymers are the intramolecular side chain and ion-pair attractions which shrink the polymer chains. In a polar solvent (N,N-dimethylformamide) the behaviour of the graft copolymers with low degree of grafting is determined by the balance between the intramolecular side chain attraction and the electrostatic interactions of the dissociated ion-pairs. The ionic groups located at the end of the side chains cause polyelectrolyte behaviour.