The hyperbranched polymer 2 was produced via triphenylphosphine initiated polymerization of the acrylate monomer 1 containing two hydroxy groups. The reaction resulting in 2 is based on a Michael-type addition followed by a proton-transfer process. The molecular weights evaluated by VPO measurements were vanging between 1170-2700 g/mol. The results of the methanolysis experiments of the polymers were used to determine the degrees of branching. that ranged between 0.45 and 0.60. In this polymerization, the hydroxy groups of the monomer and of the polymer are latent propagating species. which are converted into the corresponding anions, which are the actual propagating species active during the proton-transfer reactions. The proton-transfer occur frequently during this polymerization in order to afford the formation of hyperbranched polymers.