AbstractHybrid polymers consisting of poly(propyleneimine) dendrimers (AstramolTM) and linear poly(tetrahydrofuran) (polyTHF) were obtained by grafting living cationic polyTHF onto the dendrimer. By varying the mole ratio of polyTHF to dendrimer, either modified dendrimers, containing only a few linear polymer chains, or ‘superstar’ polymers, i.e. dendrimers containing a large number of polyTHF chains, were obtained. The average number of grafted chains per dendrimer unit, the grafting degree, could be estimated by means of 1H NMR spectroscopy. For polyTHF with molar mass of 2000 g/mol or lower, all primary amino functions of the dendrimers up to the 5th generation (32 primary amino functions) could be grafted. For polyTHF with molar mass of 4000 g/mol, the maximum grafting degree was lower than the number of primary amino groups available and decreased with increasing dendrimer generation.