The acetalization of glycerol with acetone in the presence of ethylene glycol over KU-2 and Amberlyst 70 cation-exchange resins and beta and Y zeolites has been studied. It has been shown that the rates of conversion of glycerol and ethylene glycol over the cation-exchange resins are significantly lower than over the zeolites. The rates of conversion of the polyols over the beta zeolite are lower than over the Y zeolite. Conditions for the complete conversion of glycerol to acetal have been found. The turnover number (TON) per acid site have been determined; for example, TON = 640 min(-1) for glycerol over the Y zeolite. The activation energy is 19.9 and 46.2 kJ/mol for ethylene glycol and glycerol, respectively.