The effect of ultrasonic cavitation on the process of etherification of a coker-naphtha light fraction (IBP-85A degrees C) with ethanol using an HCl-treated zeolite catalyst has been studied. Optimal process conditions have been determined to be T = 80A degrees C, P = 0.2 MPa, and V (space) = 0.5 h(-1), under which the olefin conversion and the yield of alkyl ethyl ethers increase by 12.1 and 5.6%, respectively, and the motor octane number of the etherification product is enhanced by 6 points, with catalyst coking being reduced by 50-55%.