Since disclosing the high regression rates of liquefying fuels compared to classic fuels such as HTPB, many studies using paraffin have been reported. Although pure paraffin regresses 3 to 4 times faster than HTPB, it is not an ideal fuel for launcher applications for the following reasons: it does not provide the optimum mechanical strength, may suffer from combustion instability, and offers low combustion efficiency. The present work studies a paraffin-based blend of liquid ethanol with paraffin. Ethanol improves the mixture's combustion performance, constituting drops of liquid ethanol trapped in a paraffin binder. A nonionic surfactant was employed to emulsify the ethanol into paraffin wax. Different density values from the localized small samples (? 1 cm3) and (? 0,90 g/cm3) to the large samples of fuels (? 100 cm3) and (? 0,76 g/cm3) were observed. An analysis was made with both values. It was concluded that the values of small samples made more sense in the regression rate analysis of the fuels. Thermal analyses of TGA/DTG were conducted to evaluate the activation energy during the decomposition of the fuel grains (paraffin, two blends of paraffin/ethanol fuels). Results showed that paraffin/ethanol fuel blends decompose more quickly than paraffin. Tests were performed in a two-dimensional combustion chamber with a quartz window, and the fuel formulations' combustion efficiency was analyzed. Both paraffin/ethanol fuels showed higher combustion efficiencies than paraffin. Two test batteries were performed in a hybrid rocket motor. The first battery evaluated statistically the performance of the hybrid rocket engine with each fuel type, and the second evaluated the performance and the regression rate of each fuel type optimized. There was no difference in performance for the first battery using the paraffin and ethanol samples in the condition tested. On average, the paraffin/ethanol fuels showed lower regression rates and thrust and higher specific impulse and combustion efficiency than paraffin in the second battery test. Chuffing was observed with the paraffin tests on both test batteries, and the paraffin/ethanol fuels showed more stable combustion than paraffin fuel.