In the present paper the kinetics of ethoxylation and of propoxylation of ethylene glycol catalyzed by KOH have been studied. The ethoxylation of ethylene glycol occurs with a rate that initially is higher than that observed for a fatty primary alcohol, while the propagation rate is practically the same. A kinetic model based on the reaction mechanisms similar to the one developed for fatty alcohols has been used for interpreting ethoxylation kinetic runs and the corresponding kinetic parameters have been determined. The propoxylation reaction occurs following a more complicated reaction scheme considering that the reaction of a primary hydroxyl gives place preferentially to a secondary one and this last is less reactive. A kinetic model has been developed for taking into account this peculiar behavior and the corresponding kinetic parameters have been determined. Independent experimental runs have been performed to evaluate densities of any possible reaction mixture and the corresponding ethylene and propylene oxide solubilities.