The aim of this study was to gain information on the influence of the core moiety on the kinetics of the synthesis of hyperbranched polyesters based on 2,2-bis(methylol)propionic acid (bis-MPA). Bis-MPA was esterified in the melt using sulfuric acid as a catalyst, yielding a highly polydisperse polyester. Bis-MPA was also esterified with different polyols as core moieties. The parameters varied were polyol structure, reaction temperature, and amount of added catalyst. A stoichiometry of 1:1 for carboxylic- and hydroxyl groups on the polyol was used. The reaction rates were found to be strongly dependent of the miscibility of bis-MPA and the polyol. Higher concentrations of catalyst lead to higher rates of reaction. Tris(methylol)propane (TMP) and bis-MPA exhibited the highest rate of reaction, which is due to the low melting point of TMP and good solubility of bis-MPA in the TMP melt.